or representative genera, and sometimes even of the same or representative species, in both the north and south temperate provinces, which genera or species are altogether absent from the tropical zone. Very much the same thing is found with plants, and here we account for it by supposing that the temperate forms have migrated along the meridional chain of mountains which crosses the tropics in America; and it seems necessary to suppose that the marine forms which are found in both temperate zones have migrated across the tropics in the cold layers of water which underlie the warmer ones. It would be possible to pass from the north to the south hemisphere in water never exceeding 60° F. without ever having to descend so low as 1000 feet, at which depth seaweed is found, and consequently to which light can penetrate. But although this may possibly account for the distribution of the fishes, mollusks, and crustaceans, it seems hardly a sufficient explanation of the fact that the ancestors of the whales and seals which at present inhabit the Arctic and Antarctic Oceans must once have crossed the tropics; for, being air-breathing animals, they would be compelled to come to the surface for respiration. A still greater difficulty is found in the distribution of some of the fresh-water fishes of S.E. Australia, Tasmania, New Zealand and Patagonia, which are closely allied; in some cases, indeed, the very same species occurring in S. America, New Zealand, and Tasmania. It is true that all these fishes go to the sea for a short time every year to spawn, but they could not possibly cross the wide and deep oceans that now separate these countries, and in order to account for their distribution, we are compelled to suppose that the physical geography of the Southern Hemisphere was at one time very different from what it is now.

In taking a general view of the subject, we see that the land regions, with the exception of Arctogæa, run north and south, while the marine provinces run east and west. This is easily accounted for by the present distribution of land and water, combined with the former submergence of the Isthmus of Panama, and, at an earlier date, with the existence of an ocean connecting the Mediterranean with Japan. The conclusion is that animals would arrange themselves in circumpolar zones, according to climate, were it not for the existence of barriers to migration. A good example of the effect of barriers is seen in the Gulf of Bothnia, which contains exclusively a Celtic fauna, while the White Sea and the coast of Norway in the same latitudes have Arctic faunas.

Another conclusion we arrive at is that the present configuration of the different regions, both land and marine, dates, in its main outlines, back to the Miocene or perhaps even to the Eocene period, while during that time the sub-regions and districts have in many cases been considerably modified, because we see that migration has often taken place along routes that are at the present day impassable. Beyond the Eocene period we cannot go. There is no evidence that zoological distribution was the same during the Mesozoic era as at present, and none that were any distinct regions at all in the Palæozoic era.

ON SOME HITHERTO UNRECORDED PLANT

STATIONS.

BY T. F. CHEESEMAN, F.L.S.

No one can examine the broken and fragmentary evidence we possess respecting the distribution of our native flora without granting that a wide field is open for future research. No doubt much preliminary and useful work has been done, considering the youth of the Colony, and that most of its inhabitants have of necessity to occupy themselves with more personal and pressing matters than that of tracing the range of a plant, of finding out how high it ascends the mountains, or of ascertaining the physical character of the localities in which it grows. But a noteworthy difference exists between what is already recorded and what is required before it will be possible to compile a "Cybele Nova Zealandiæ " similar in scope, and equal in point of detail, to the "Cybele Britannica" of the late Mr. H. C. Watson. Material might, however, be more rapidly collected if our working botanists would from time to time publish in the JOURNAL OF SCIENCE, or elsewhere, notices of new or unpublished localities, using, of course, due care in the identification of the species. Probably this system, if once established, would soon lead to the formation of a Botanical Exchange Club, similar to the well-known institution of this name in England, which has so materially assisted in bringing the knowledge of plantdistribution in the British Isles to its present satisfactory condition.

So far as I am aware, the plant-stations given below have not been previously published. With most of them I have been acquainted for years, and it is possible that some may also be known to other botanists, although I have no knowledge that this is the case.

Pittosporum virgatum, Kirk.-Between Coromandel and Kennedy's Bay; abundant. The other known localities are the

Great Barrier Island and Whangaroa.

Pittosporum kirkii, Hook, f.-Summit of Maungataniwha, Hokianga, alt. 2500ft.; the most northern habitat yet recorded. Hills to the north of the Pirongia Mountain; its southern limit so far as is at present ascertained.

Pomaderris edgerleyi, Hook, f.-Bare hills along the Northern Wairoa River, from Te Koporu to Dargaville, and stretching across to the sea south of Maunganui Bluff (T.F.C.) Between Orewa and the Wade (Rev. J. Bates). The stations previously recorded for this local plant are :-Cape Colville Peninsula, from Tarara to Cabbage Bay; Mount Manaia, Whangarei; and the North Cape District.

Discaria toumatou, Raoul.-Sandhills to the north of Port Waikato; probably its extreme northern limit.

Myriophyllum pedunculatum, Hook, f.-Lake Pupuke, near

Auckland.

Hydrocotole dissecta, Hook, f.-Swampy forests by the Northern Wairoa River; abundant. Also plentiful in several localities. between the Auckland Isthmus and the Middle Waikato.

Coprosma fætidissima, Forst.-Attaining its most northern station between the Thames and Tairua (J. Adams). Also gathered by the same gentleman on Te Aroha.

Erechtites prenanthoides, D.C.—Kaueranga Valley, Thames; a few plants only. Not previously known northwards of Cambridge in the Waikato, and Tauranga on the East Coast.

Senecio latifolius, Banks and Sol.-By the sides of streams in the Hunua Ranges, south of Auckland; probably its northern boundary.

Dracophyllum strictum, Hook, f.-Head of the Kaueranga River, and hills near Puriri, Thames (J. Adams). This gives a marked extension to the range of the species, the nearest locality previously known being the Tamahere Narrows, Waikato.

Myosotis spathulata, Forst.-Moist ground by the Papakura River; the most northern station known to me.

Myosotis antarctica, Hook, f.-Sea-cliffs north of the Manukau Harbour; not common. A minute depauperated variety, but clearly referable to this species.

Teucridium parvifolium, Hook, f.-Low grounds by the Thames River, near Te Aroha (J. Adams).

Mentha australis, Br.-Naturalised in many places in the Raglan district, and particularly abundant between the Mata Creek and Ruapuke, where I first observed it in January, 1877. Mr. Kirk has recently recorded its occurence in the Wairarapa ("Trans. N.Z. Inst.," 14, p. 383), and seems to consider there is a chance of its being indigenous in that locality. It is clearly an introduced plant at Raglan.

Utricularia colensoi, Hook, f.-Peaty swamps in the Middle Waikato; plentiful, especially near Ohaupo. This plant appears to have been lost sight of since its original discovery on the East Coast by Mr. Colenso many years back.

Pisonia umbellifera, Seem.-Whangape Harbour, north of Hokianga, (J. McLennan, J. Webster, F. E. Manning). I believe that this is the only known locality on the mainland, for although it is recorded in the "Handbook" from near Ngunguru and from Whangarei, I have been unable to find it in the first locality, and it is unknown to the settlers. As to the second station, I am informed by Mr. R. Mair that a single tree planted by the Maoris formerly existed on Limestone Island, in Whangarei Harbour, and that Dr. Sinclair's habitat was probably based on this solitary specimen, long since destroyed. The other recorded localities, all of which were first specified by Mr. Kirk, are as follows:-The Taranga Isles (Hen and Chickens), where it is most abundant, associated with the still more local Meryta sinclairii; the Little Barrier Island, on which also it is not un

common; and Arid Island, to he north of the Great Barrier. From information received from fishermen and others, I have little doubt that it also exists on the Poor Knights and the Fanal Isles; but I have not seen specimens from thence.

Fagus menziesii, Hook, f.-Near Table Mountain (inland from the Thames), and on Te Aroha J Adams). These habitats give a marked extension to the northern range of this species.

Ascarina lucida, Hook, f.-Of very local occurrence on the Waitakerei Range, near Auckland.

Phyllocladus glauca, Carr.-Waitakerei Range; rare. With the exception of Hokianga, this is the only station yet known on the western side of the Island.

Pterostylis barbata, Lindl. (P. squamata, Hook, f., "Handbook N.Z. Flora," now R. Br.)-Bare clay hills, near Mercer, on the Waikato River. The only other locality certainly known is Kopu (Thames district).

Juncus tenuis, Willd.-Upper Maungatawhiri Valley; banks of the Waikato, near Rangiriri; near Ngaruawahia; between Hamilton and Cambridge; Wangapeka Valley, Nelson.

Juncus articulatus, L. var lamprocarpus.-Pumiceous deposits by the Waikato River, near Rangiriri. A few plants only were observed.

Schanus nitens, Br.-Waimarama, Hawke's Bay (H. Tryon).

Carex teretiuscula, Good.-Ruataniwha Plains, Hawke's Bay (H. Tryon). Swamps in the interior of Nelson Province, alt. 1000-3000 ft.; not uncommon (T.F.C.)

Carex buchanani, Berggren.-Abundant in river valleys in the Nelson Provincial District.

Carex dipsacea, Berggren.-Mount Egmont Ranges, alt. 3000 feet (H. Tryon). Plentiful in hilly and wooded districts in Nelson (T. F. Cheeseman). This and the two preceding species were accidentally omitted from my enumeration of Nelson plants, printed in "Trans. N. Z. Inst.," vol. 14.

A pera arundinacea, Hook, f.-Banks of the Wai-iti stream near Foxhill, and in the Wangapeka Valley, Nelson. Now considered by Sir J. D. Hooker to belong to the genus Muhlenbergia. Mr. Bentham seems inclined to place it in Stipa, principally on account of its close resemblance to Stipa verticillata, Nees (Streptachne ramosissima, Trin.) See "Journ. Linn. Socy.," 19, p. 81.

Danthonia bromoides, Hook, f.-Sea-cliffs, Bay of Islands, Whangaroa, Doubtless Bay, &c.; abundant. Curiously enough, this species is not mentioned in Mr. Buchanan's list of North Auckland plants ("Trans." 2, p. 239), or in Mr. Kirk's list of additions ("Trans." 3, p. 166).

Gymnostichum gracile, Hook, f.-Low grounds by the Thames River, Kopu, Keri-keri, Puriri, &c. Mr. Bentham, in his "Notes on Graminea" ("Journ. Linn. Society" 19, p. 134) remarks that Willdenow's name Asprella has the priority over Gymnostichum. In future, therefore, our plant should bear the name of Asprella gracilis, Benth.

Lindsaya viridis, Colenso.-Banks of the Waikato, near the Tamahere Narrows (Mrs. Gubbins). Not previously known from any part of the Waikato country.

Adiantum formosum, Br.-Although this species has long been known to occur in the north of Auckland province, no one has yet specified the exact locality, and considerable misapprehension exists respecting it. In the "Handbook," the habitats of Kaipara and Whangarei are given, on the authority of Mrs. Jones' little book. This statement has been copied into several later publications, although it is certainly incorrect, as the plant is not known in either district, properly so called. Mr. Kirk has pointed this out (“Trans. N. Z. Inst.,” 3, p. 173); but, being misled by imperfect information, has fallen into the error of assigning the West Coast as the proper habitat. The exact locality is the valley of the Northern Wairoa River. In a boat voyage made up this stream in 1875, specimens were first observed about six miles above Dargaville; but the plant is apparently rare until the "great bend" of the river is passed. It then becomes plentiful in the swampy forests fringing the banks, in many places covering acres of ground, and attaining a height of over four feet. A little below the old Mission Station at Tangitiroria it thins out, and is only occasionallly seen; while before reaching the junction of the Mangakahia and Wairua it has altogether disappeared.

Cheilanthes tenuifolia, Swz.-Mohaka River, Hawke's Bay (E. Craig).

Phylloglossum drummondii, Kunze.-Near Papakura; hills by the Waikato River, near Mercer; north-western side of Lake Waikare. Not previously recorded from the south of the Auckland Isthmus.

RECENT VIEWS ON THE TRILOBITES.

BY CHARLES CHILTON, B.A.

In the "Bulletin of the Museum of Comparative Zoology at Harvard College," Vol. VIII. (April, 1881), there is an important paper by Mr. C. D. Walcott, intituled "The Trilobite: New and Old Evidence relating to its Organisation." As this may not be accessible to many in New Zealand, a short account of the results arrived at by Mr. Walcott may not be out of place.

The trilobites, as everyone is aware, are fossils that have been known for a very long time; immense numbers of specimens have been found, many of them very perfect; yet for long nothing was known but the hard dorsal shell and the hypostoma; and though we now, thanks to Mr. Walcott's laborious researches, know a little about the appendages, still our knowledge is very fragmentary and unsatisfactory.