ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 363 



His. The most remarkable point in tlie embryo was that, although there 

 was no reason for supposing that the condition was due to pathological 

 causes, there was a certain want of symmetry in the development of the 

 two sides of the body. The left side was, for several organs, and 

 especially for the cerebral vesicles, in advance of the right. The author 

 cannot say whether this asymmetry is peculiar to man, and asks if it has 

 any relation to the functional predominance of the right side of the body 

 in the adult. He asks if it is a result of a habit or the consequence of 

 anatomical peculiarity of the embryo. But he is unable to answer these 

 questions. 



Development of Bony Fishes.* — M. F. Henneguy gives a detailed 

 account of his observations on the development of Bony fishes ; the chief 

 object of his investigations has been the trout From his studies, as 

 from those of Lis predecessors, it is obvious that the embryology of the 

 Teleostei is particularly interesting as introducing us to a special mode 

 of development which sharply sej)aratcs these animals from other fishes; 

 such are the constitution of the egg, the format'on of the gastrula, the 

 presence of a rudimentary primitive line, the primordial constitution of 

 the nervous system and of some other organs ; and these characters 

 indicate that the Teleostei form a divergent branch of the piscine 

 phylum. The facts of Embryology corroborate those of Comparative 

 Anatomy, and show us that, even if in certain points the Teleostei are a 

 degraded type of fish, we find in them the earliest indications of the 

 distinctive characters of the higher Vertebrata. 



Structure of Amphioxus laneeolatus.f — Prof. E. Eay Lankester has 

 a contribution to the knowledge of this interesting animal, which is 

 illustrated by, inter alias, figures which rej)reseijt, in semi-diagrammatic 

 form, the structure of AmpJiioxus, not merely as seen in sections or 

 dissections, with all the imperfections necessarily arising from the action 

 of preservative media, but as reconstructed and corrected from numerous 

 specimens, so as to give as nearly as may be a true view of the undis- 

 torted organism. 



After some account of the external marks and numerical character- 

 istics, in which the numbers of the myotomes, of the dorsal and ventral 

 fin-rays, and of the preoral cirri are considered, attention is drawn to the 

 size and importance of the post-oral tentacles or tentacles of the 

 sphincter oris, and to the fact that there are no " ventral canals " beneath 

 the plaited ventral wall of the atrium. There are three distinct kinds 

 of spaces containing liquid in the living state ; these are the atrial 

 cavity, the enteric cavity, and hgemo-lymph cavities. The last break up 

 into numerous groups, such as the vascular system which is in open 

 cont nuity with the suprapharyugeal and perienteric portions of the 

 coelom ; the perivascular spaces of the dorsal aortse ; the perigonadial 

 coelom ; various lymph spaces and canals ; tlie neuraxial canal ; the 

 myocoelomic pouches or intra-muscular lymj)h-sj)aces of the head ; and 

 the series of intra-skeletal lymjih-spaces of the myotomes. The 

 distorting action of the reagents used for hardening specimens causes 

 the correct conclusion as to the existence of spaces in the body of 

 Amphioxus to be a very difficult matter. 



The vascular system appears to be in a condition of degeneration, as 



* Joum. Anat. et Physiol. (Robin), xx v. (1888) pp. 413-502, 525-617 (4 pis.). 

 t Quart. Journ. Micr. Sci., xxix. (1889) pp. 365-408 (5 pis.). 



