50 Bibliographical Notices. 



Salmons. It is confined almost to a journal of facts which seem to 

 have been very carefully observed, M. Vogt having abstained, in a 

 great measure, from attempts to generalize or to draw a comparison 

 between the embryology of other classes, either higher or lower, 

 for which purposes he considers that materials do not exist. " Em- 

 bryologie, envisagee comme science, n'a guere ete jusqu'a present que 

 l'histoire du developpement de l'ceuf de la poule, et Ton s'est gene- 

 ralement borne a indiquer les differences qu'on remarquait a l'egard 

 de certains organes dans d'autres animaux, souvent sans avoir fait 

 une etude speciale de ces dernieres ; ce qui a donne lieu plus d'une 

 fois a des rapprochemens inexacts." The work is divided into four- 

 teen chapters, of which we give the titles. 



Chap. I. L'ceuf avant la fecondation. — A general description of 

 the ovum in this state is given. The vitellus and vitellary mem- 

 brane are the parts which increase most rapidly ; but the germina- 

 ting vescicle and germinating spots increase also, though in less pro- 

 portion. The growth of the latter has been denied, but it is so evident 

 in the ova of the C.palea as to be easily perceived. The surface of the 

 ova is stated to be smooth and without any of that viscous covering 

 which assists in attaching those of many other fishes to plants or stones, 

 &c. M The ova of C. palea, like that of all the Salmons, is delivered 

 free, and left to the mercy of the waves." This we have considered 

 as one of the points of distinction in the ceconomy of the Coregoni 

 and the Clupeadce, compared with the true Salmons : in the first, the 

 ova are deposited " on the waters," and impregnated at the same 

 time ; among the latter they are deposited on the ground, and are 

 never removed from the furrow and gravel where they have been 

 placed by the parent fish. 



Chap. II. Fecondation ; condition de developpement; maladies de l'ceuf; 

 methode d' observation. — The manner in which M. Vogt artificially 

 impregnated the ova is described, differing little from that practised 

 by Mr. Shaw of Drumlanrigg; various causes, however, seem to 

 influence their development, some of which appear curious. " To 

 bring them successfully to perfection, I believe it is necessary that 

 they should be kept in the same water in which the fish has been accus- 

 tomed to spawn. I have had experience of the fact, that the ova of 

 the salmon trout which spawns in the rivers are destroyed when 

 placed in the waters of the lake ; while those of C. palea which 

 spawns in the lake itself do not succeed in the water of the rivers. I 

 have even been unable to bring to their term the ova of the pike of 

 the marshes, which spawns earlier than that of the lake, though the 

 fishes do not differ generically." Sudden violent changes of tem- 

 perature are fatal, but a gradual cold, even though the ova were en- 

 closed in ice, only retarded the progress. A disease attacks the ova 

 in various stages, and is very fatal to the newly-hatched young ; it 

 is the growth of a cryptogamous plant or species of mould, consi- 

 dered analogous to that which M. Hannover has observed on differ- 

 ent tritons, and perhaps also somewhat similar to that which has of 

 late received attention in this country as vegetating upon living 

 fishes. 



