tray, those with a non-mathematical turn have seldom shone in physics.

No branch of physical science can be taught well without the requisite appliances. Certainly in many cases these need not be of an expensive character, and the ingenious teacher can illustrate many of the phenomena of heat, light, sound, and chemical action by means of apparatus and utensils in every day use. But to elucidate his whole subject, he must have certain special kinds of apparatus, and these are possessed by few of our schools. Chemistry in particular requires a somewhat elaborate stock, both of material and apparatus, and without these it is better policy on the part of teachers to take up some other subject which would more easily be illustrated.

Electricity (and magnetism) also require apparatus, and that of a somewhat expensive kind. My own opinion, which will not perhaps meet with much favour from physicists, is that this science is best left alone until the principles of some of the allied sciences are mastered. Its phenomena are not readily presented to the mind in a thinkable form, and, as a matter of fact, a very considerable familiarity with these phenomena may be acquired without any corresponding knowledge of the principles underlying them. While both things are important, the knowledge of principles is much more so, from an educational point of view, than the practical acquaintance is.

Again in this connection I am tempted to review the position. assigned to the physical sciences in the University Junior Scholarship examination. In the list of subjects scheduled, inorganic chemistry, sound and light, heat, electricity, and elementary biology, are all placed in the same standard as far as values are concerned, 500 marks being assigned to each. Those who are practically acquainted with, and have taught these subjects, know that to attain equal results in each, very different amounts of teaching and of study are required. No doubt examination papers could be set so as to reduce all to an equal value, but in practice this is rarely done. It requires a far more considerable amount of study to be able to answer questions over the wide fields of chemistry and of biology than it does over the more limited and definite subjects of heat, light, sound, and electricity. I can point to more than one instance of pupils who have been engaged for two years or more on the study of one of the wider subjects, but who, six months before their going up for examination, dreading that they could not compass all the field, have thrown it up, taken up one of the four above-mentioned (which was previously unknown to them), and with that brief" cram out of a text-book, have passed successfully. This is certainly not one of the results which the Senate of the University desire, and though such work under the best devised scheme of examination will always be more or less possible, still it is neces

I leave out of account the “Elementary Mechanics of Solids and Fluids,” as I have no practical acquaintance-as a teacher-with the subject.

sary to take those precautions which will tend to reduce it to a minimum.

As every examiner knows, there are two limits to be equally avoided in the setting of papers. One is, not to set them too low, as then the subject is taken up solely as a "pass" one, and the standard is unworthily lowered. The other is of course not to set them too high, as in that case candidates are apt to avoid the subject altogether as one which "does not pay." In my own humble opinion the former tendency has been shown in our University examinations in the papers set on physical sciences. This may be remedied to some extent by amalgamating heat and electricity as one subject, as sound and light are treated. Elementary biology also should give place to botany and zoology.

I hope the day is not far distant when every candidate for University Honours will require to pass in one branch each of physical and natural science. To attain this desirable consummation, all occupied in teaching these subjects must work earnestly, but judiciously, not obtruding their dogmas offensively, nor blazoning them abroad as the universal panacea which is to revolutionise the existing state of things. On the contrary, they must possess their souls in patience, must build up in the minds of the rising generation a strong conviction that the scientific method is the right one, and must show to the intellectual world at large that the subjects which they teach possess a high educational value, and one which will be of lasting and practical utility to its possessors.

CORRESPONDENCE.

MARINE CADDIS-WORMS.

SIR,-It may interest your entomological readers to learn, with reference to the marine caddis-worm found last year by Professor Hutton in Lyttelton harbour, and recently described by Mr. R. M'Lauchlin in the Proceedings of the Linnean Society, that some months ago I found a specimen of a very similar trichopterous larva among seaweeds between tide marks in Port Jackson. The case was composed of minute fragments of algæ, and the form of the head and of the abdominal appendages resembled closely that of the corresponding parts of the New Zealand species, as figured by Mr. M'Lauchlin.-I am, &c.,

Sydney, Oct. 4th, 1882.

WILLIAM A. HASWELL.

NEW ZEALAND MOLLUSCA OF THE "CHALLENGER" EXPEDITION.

BY REV. R. BOOG WATSON, F.L.S., etc.

Extracted from the Linnean Society's Journal-Zoology, 1879, etc.

DENTALIUM DIARRHOX, Watson. P.L.S. xiv., p. 511.

St. 169. July 10, 1874. Lat. 37° 34′ S., lon. 170° 22′ E., N.E. from New Zealand. 700 fms., Grey ooze, 4 specimens.

Animal-Mantle white, body pale yellow. Captacula many, fine, long, and equal, with small ovoid points. Foot and collar those of a true Dentalium.

Shell.-White (chalky), but porcellanous beneath the surface; rather straight, with a considerable bend near the apex, of rather rapid expansion from a very fine apex. Sculpture. The whole surface is faintly marked with scarcely-impressed longitudinal lines of very equal interval (about 0.0055 apart); transversely it is very faintly scratched all over by very slight lines, which run elliptically round the shell. The apex has a very narrow slightly ragged fissure, about 0.027 in. long, which lies unsymmetrically on the convex curve. L.? B. 0.9.

This differs from D. leptosceles, W., in being more curved and more conical. It resembles in form the young of D. lubricatum, G. B. Sow., B.M., "from Australia"; but in that the transverse striæ are much less oblique, and the surface is lubricate and polished.

CADULUS COLUBRIDENS, Watson, l.c. xiv., p. 523.

St. 169. July 10, 1874. Lat. 37° 34′ S.; long. 179° 22′ E. N.E. point of New Zealand. 700 fms., Grey ooze, I specimen. Shell.-Like an adder's fang; long, sharp, bent, very slightly flattened, swollen near the broader end. The swell, which is faintly angulated and is at one-fourth of the length, is chiefly on the convex curve, but is visible on the concave curve too. From the angulation the curve is very equable in either direction. About two-thirds a long towards the apex, it bends more back. The shell is thin, brilliant, semi-opaque, white. Sculpture.-Very faint and fine scratches on the lines of growth. Mouth large, oval, very slightly flattened on the front side, from which the thin sharp edge is obliquely cut off towards the convex curve. The posterior opening is much smaller, nearly round, and the edge is thin and chipped. L. 0.58; B, at mouth 0.067, at swell o.1, at apex 0.033.

This is twice the size of C. gadus, Montague; but it resembles that in the angulation, which, however, is here more marked at the summit of the swelling; its expansion from the smaller end

is much more gradual, and its contraction from the angulation on to the mouth is more rapid.

TURRITELLA CARLOTTA, Watson, l.c. xv., p. 222.

St. 162. April 2, 1874. Lat. 39° 10′ 30′′ S.; long. 146° 37' E.. Moncœur Island, Bass Straits. 38-40 fms., sand.

St. 167a. June 27, 1874. Lat, 41° 4' S.; long. 178° 19′ E. Queen Charlotte Sound, New Zealand, 10 fms., mud.

Shell.-High, narrow, conical, with slightly-impressed suture and an angular flattened base, thin, translucent, with fine ruddy spiral threads. Sculpture.-Longitudinals-these are fine, thread-like, slose-set curved lines of growth. Spirals-there are two principals, two secondary, and very many minor spirals, but the relative value of these varies a good deal; they are little raised, but distinct. The base is covered with fine crowded spirals, of which those near the edge are stronger than the rest. The microscopic system of spirals is fine, sharp, and distinct. Colour, yellowish ashy white, with a suffused ruddy brown on the upper part of the whorls, and a stronger shade of the same colour defining the more important spirals. The colour becomes altogether paler up the spire, and the apex is white. Spire very perfectly conical; but the profile lines are interrupted by the impressed sutures. Apex small, rounded, smooth, and glossy, consisting of 11⁄2 embryonic whorl; the next whorl is slightly angulated, after which the regular sculpture begins. Whorls 15, very slightly convex on the sides, contracting gradually upwards into the suture; towards the bottom of the whorl the contraction into the suture is shorter, straighter (i. e. less convex), and more rapid; they are of very gradual and regular increase. Towards the upper part of the spire the curve of the profile line of each whorl becomes increasingly stronger. The base is flat, very slightly conical, sharply angulated, and not contracted at the edge. Suture very slight, but well defined. Mouth small, angularly rounded, a little higher than broad. Outer-lip a little drawn in and advancing on the edge of the base. descends straight to the lower outer angle, is flat across the base, and a little patulous in front of the pillar-point. The generic sinus in the outer-lip is parabolic in form. Inner-lip.-There is not (though the specimens are full-grown) even a glaze across the body nor round the base of the pillar; but on older specimens this may probably exist. Pillar is a little concave, rather direct, with a thin rounded edge. Epidermis a very thin and delicate calcareous membrane obviously not extraneous; it adheres to the top of the spirals, and stretches across their furrows. It is sparsely cleft by minute gaping rents in the direction of the lines of growth, and the microscopic sculpture of the shell is traceable in it, but rather on its under than its upper surface. H. 0.95, B. 0.28, least 0.25. Penultimate whorl, height 0.15. Mouth, height 0.16, breadth, 0.14.

This species has some resemblance, both in form and sculpture, to T. knysnaensis, Krauss, but it is narrower, suture less impressed, whorls not so convex; the embryonic apex is very like, but in the "Challenger" species it is a little more swollen and depressed.

NATICA AMPHIALA, Watson, l.c. xv., p. 260.

St. 169. July 10, 1874. Lat. 37° 34′ S.; long. 179° 22' E. N.E. from New Zealand. 700 fms., Grey ooze. Bottom temperature, 40° F.

Shell.-Thick, depressedly globose, with a small scalar, rather elevated spire, and a narrow obliquely-pointed base; pale yellow, umbilicated. Sculpture.-Longitudinals-There are many fine close-set lines of growth. Spirals-There are a few faint traces of obsolete lines and furrows; there is a slight angulation round the mouth of the umbilical pore. Colour is slightly brownish yellow, but is pure porcellanous white below the epidermis, which is thin, slightly puckered, smooth, not glossy, persistent. Spire short. but abrupt and scalar. Apex seemingly rather large, but abraded, Whorls, 4-5 narrow, flatly rounded, of gradual increase to the last, which is disproportionately large, especially towards the mouth. Suture strong, slightly channelled, almost quite horizontal. Mouth large, oval, very little oblique, and rather straight, scarcely pointed above; it is more than two-thirds of the whole height. Outer-lip sharp, but strong, patulous throughout. Inner-lip straightish, but slightly concave in its whole length; it is expanded on the labial callus, which is thick, but has no labial nor umbilical pad; the front of the pillar is thickened and flattened back on the very indistinct circumumbilical carina. Umbilicus is a rather coarse, pervious, smallish round hole, hardly encroached on at all by the inner-lip. Operculum membranaceous thinnish, of a yellow colour, with a dark maroon outer edge which does not quite coil into the centre. H. 0.27, B. 0.25; penultimate whorl, height, 0.07; mouth, height 0.21, breadth 0.17.

This species combines a flattened globose form with a prominent pointed base and a small raised scalar spire, in a way that is very peculiar; so much so, indeed, that it almost recalls an Amphibola. A. tenuis, Gray, in particular, has features of resemblance. It very slightly resembles N. nana, Möller, from Greenland; but the body whorl is more depressed, the spire is more enserted, and the umbilicus is not closed, as in that species.

(To be continued).