594 



NATURE 



\April 24, 1879 



meet, but is probably formed from the latter. The infundibu- 

 lum is beginning to grow towards the pituitary body, and close 

 in front of it are seen the optic nerves which are still hollow. 

 Rudimentary olfactory lobes are seen where the solid olfactory 

 nerves are given off. 



Cartilage is forming in the base and sides of the skull, as well 

 as in the ear-capsules. The notochord ascends high into the 

 head and is slightly curved over at the end. The azygous 

 prochordal element, or inter-trabecular bar, is of equal size to 

 the trabeculoe, which are now articulated with the hind part of 

 the basis cranii, in front of the base of the ascending wall. 



This stage is especially valuable in helping to a clear con- 

 ception of the true nature of the prochordal part of the 

 trabecular. 



T^rd Stage, \\-in. long. — In this stage the head has almost 

 acquired the adult form, and the carapace is well marked out. 

 The abdominal region is flattened to give rise to the plastron. 

 The limbs have also practically acquired their adult form, and 

 the heart is fairly inclosed in the thorax. 



The post-oral clefts are now filled in, and the skull is 

 thoroughly chondrified, foiTning a cartilaginous trough. The 

 trabeculce and inter-trabecula have grown into a high septum 

 between the eyes and nose. From the former, the orbito- 

 sphenoids grow, and the alisphenoids extend from the orbito- 

 sphenoids to the auditory capsules. Ossification now begins in 

 the palate. 



The notochord turns round in the post-clinoid upgrowth of 

 of the basal plate, and the sheath in its descending part becomes 

 solid, and ends behind the lobules of the rudimentary pituitary 

 body as a tear-shaped drop or lump of cartilage. If the head 

 had been straight, this drop might have reached its fore end, 

 directly below the first nerves. The inter-trabecula is a con- 

 tinuation of the same skeletal tract as the sheath of the notochord, 

 and it reaches to the actual end of the head, while the drop of 

 cartilage approaches the organic end. 



^h Stage — two-thirds ripe — 3-?«. long. — In these embryos 

 nearly all the adult structures can be seen. The epipterygoid is 

 still, however, a cartilaginous hook hanging down from the 

 quadrate. The colimiella is well developed, and its shaft is 

 ossified. 



The parietals have grown down the sides of tlje skull causing 

 the alisphenoids to be absorbed to a great extent. The investing 

 bones are now rapidly developed, but much of the endocranium 

 is still soft. 



5/A Stage — ripe — 4/«. long. — The processes of development 

 and ossification have now gone so far that little can be remarked 

 upon as differing from the adult. The epipterygoid, however, 

 which is wedged in between the descending parietal and the 

 pterygoid, is now a distinct bone, but its apex permanently 

 touches the apex of the pedicle of the quadrate, from which it 

 was segmented. 



The development of C/4if/(3«^ w^'^iJj corresponds in all essentials 

 with that of the common snake ( Tropidonotus natrix) and lizard 

 (Lacerta agilis) which the author has recently worked out ; but it 

 is well worth remarking that that which distinguishes the chelo- 

 nian from other reptiles is already manifest in the first stage. 



The author considers that there are several things in the head 

 of the vertebrate embryo which are evidently of a segmental nature. 

 Firstly, nerves in the head corresponding to spinal nerves. These 

 constantly fork over clefts, which are also signs of segmentation. 

 Thenumber of inferior arches, whether pre-cral or post-oral, also 

 indicate the number of segments that may exist in the head of 

 a vertebrate. At any rate, wherever there is any diverticulum 

 of a pleuro-peritoneal cavity, although divided off from that of 

 the body by the clefts, there is that which corresponds to a 

 somatome. By this last evidence there is at least one homologue 

 of a pre-oral somatome, and if we go by the nerves, clefts, and 

 cartilages, there are more. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



' The Council of King's College have decided to give the name 

 "Wheatstone Laboratory" to the physical laboratory of the 

 College, in honour of Sir Charles Wheatstone, who was for 

 some years Professor of Experimental Philosophy in the College, 

 to which he also bequeathed his valuable collection of physical 

 apparatus. The report of the laboratory work shows that the 

 physical laboratory was established in the year 1 868, and that 

 during the eleven years of its existence about 250 students 



have been trained in it in the various branches of practical 

 physics. The average number of occasional students — i.e., 

 students who are engaged in research and do not attend 

 with any special class, has been nine a year during the last five 

 years. Among these are graduates of the older universities, who 

 come to reside in London after they have completed their term 

 of residence at the University. Engineering students in their 

 third year's course have the privilege of working in the labora- 

 tory free of charge. There are also special practical classes 

 which have been well attended, for the Bachelor of Science and 

 the Preliminary Scientific M.B. Examinations of the University 

 of London, and also special classes for evening class students 

 who are engaged in business during the day-time. In all there 

 are not less than forty students now engaged in practical w ork 

 in physics in " the Wheatstone Laboratory " in King's College. 

 The Laboratory is greatly in need of endowment, in order 

 that an additional Demonstrator may be appointed, and the 

 usefulness of the laboratory still further extended. 



SCIENTIFIC SERIALS 



journal of the Franklin Institute, March. — We note the 



T — T 

 following papers in this number : — Concerning — 1— — 9» or the 



Ti 

 limit of efficacy of steam-engines, by Mr. Klein. — Gauging- 

 and measuring-implements, by Mr. Richards. — A new engine- 

 governor, by Prof, d'Auria, — Conical arches at South Street 

 Bridge, Philadelphia, Pa., by Mr. Stauffer. — Graphic freight 

 diagrams, by Mr. Dudley. 



Bulletin de V Academie Royale de Belgique,mo. i, 1879. — This 

 contains an interesting paper by M. Niesten, on the colours of 

 double stars, which he was led to study by the variations in 

 intensity and colour of planets in relation to the sun. He finds 

 that in systems which allow of connecting the colours with 

 position of the satellite in its orbit, the principal star is white or 

 pale yellow when the companion is at periaster, whereas in 

 other positions it is yellow, gold yellow, or orange. The 

 companion follows the principal star in its fluctuations of 

 colour, and often exceeds it as it removes from periaster 

 (where it is mostly white, like the principal). In per- 

 spective groups, the companion is nearly always blue, by 

 an effect (the author suggests) similar to that by which 

 mountains on the distant horizon look blue (and pointing to a 

 gaseous medium in celestial space). — M. Delarge describes some 

 instructive experiments on the telephone, applied in the neigh- 

 bourhood of ordinary telegraph line^ Secrecy can be insured for 

 telegrams, with dial-apparatus or that of Hughes, but the former 

 is objectionable as leaving no trace, and the latter is very ex- 

 pensive and delicate. Hence recourse should generally be had to 

 cipher. — M. Marchal contributes a revision of American He- 

 deracese, describing eighteen new species and a genus. — M, 

 Chevron is led to deny the inalterabihty of tricalcic phosphate 

 by citrate of ammonia ; but the use of this solvent for separation 

 of the phosphate may give sufficiently exact results if a too great 

 excess of the citrate solution be avoided. — We further note an 

 analysis of, and reports on, the second part of M. Lagrange's 

 work on the origin and establishment of astronomical movements,, 

 wherein is assumed that the material atoms were .originally dif- 

 fused through space in a state of rest and at the absolute zero of 

 temperature, and endowed simply with reciprocal attraction. — 

 M. Malaise writes on arsenopyrite, or mispickel, and on the 

 arsenical water of Court Saint-Etienne. 



No. 2. We have here a paper by M. Saltel on a mathematical 

 paradox, and on a new character of 'decomposition due to the 

 presence of multiple lines. — M. van Beneden records the receipt 

 of some interesting fossils of cetacea from marls of the tertiary 

 epoch in Croatia. 



The Revue Internationale des Sciences (January-March, 1879), 

 contains the following papers of interest : On the cell soul and 

 soul cells, by Ernst Haeckel,— On the nutrition of plants, by J. 

 L. de Lanessan, — Analysis of two memoirs on Noctiluca, by 

 G. Carlet.— On a monstrous skeleton of a batrachian, by F. 

 Lataste. — Researches on Bacteria, by Dr, Kcch, — On vascular 

 innervation, by MM. Grutzner and Heidenhain. — On the action 

 of light and heat upon moving spores, by E. Strassburger and E. 

 Stahl. — On contagious diseases and disinfecting agents, by Prof. 

 Naegeli. — General observations on fertilisation, by E. Strassbur- 

 ger. — On a technical process for the study of fish embryos, by 

 F, Henneguy.— On the retina red and its relation to vision, b| 



