Miscellaneous. 257 



yolk-sac has disappeared, though the animal is shorter than a larval 

 form two months before extrusion. Indeed, it is likely that the 

 yolk was absorbed before extrusion, otherwise it would not have 

 escaped attention so long. 



In examining a number of pregnant females this winter, I have 

 been struck with the frequent occurrence in the earlier stages of one 

 or more deformed embryos. The deformity appears confined to the 

 caudal region, which is bent, or even spirally twisted. Ryder* and 

 others have shown that in some normal oviparous fish the tail of the 

 embryo is affected in a similar way by unfavourable conditions of 

 temperature. But it does not appear that any so-affected embryos 

 hatched. 



Here it is evident that the deformity, however caused, has had no 

 effect on the embryo beyond retarding its growth. The little 

 creature has the ordinary proportions of a larval form of the same 

 length, and appears active and healthy, feeding greedily on Copepods. 



The young blennies at this age lie quietly at the bottom of the 

 vessel in which they are confined, ever and anon making a dart at 

 a passing Copepod. They rarely rise into midwater, though Cope- 

 pods are much more abundant near the surface than at the bottom. 



On the Relationship of the Annelida and Mollusca. 

 By M. A. Giard. 



In the Report on the great prize in the physical sciences pub- 

 lished in the 'Comptes Rendus' of the 30th December, 1889 (p. 1055), 

 it is said: — "What especially merits attention in the memoir of 

 M. Roule is the place which he assigns to the Annelida in the 

 animal series. He makes them near relatives of the Mollusca." 



With reference to this passage M. Giard remarks that long before 

 both Roule and Hatschek he expressed the same opinion. In 1876, 

 at the close of a note upon the development of Salmacina Dysteri, 

 Huxl., he wrote as follows f : — 



'■'■General results. — The formation of the organs of sense inde- 

 pendently of the nervous system, and before the completion of that 

 system, the presence of ectodermic respiratory organs, the late origin 

 of the circulatory apparatus, are so many characters approximating 

 the embryo of Salmacina to that of the Mollusca. The divergence 

 between the Mollusca and the Annelida only commences after the 

 Trochosjjhm-a-si&ge, and even after this stage the morphological 

 agreements and histological resemblances between the two types are 

 still very numerous. The relationship of the Mollusca and the An- 

 nelida is certainly nearer than that of the latter to the ArtJrropoda ; 

 the existence of metameres in the Arthropoda and the Annelida has 



* ' Report of Commissioner U.S. Fish and Fisheries Commission,' ]*&■'>, 

 p. 532. 



t ' Comptes Rendus," January 24, 1876. 



