ZOOLOGY. 617 



who has examined four species — 8. innictata, S. fnsiformis. 8. hicaudata, 

 and S. democratica. The sum of his researches has been thus recorded 

 in the Journal of the Eoyal Microscopical Society: "'The developmental 

 process of Saljyais so peculiar that it is very difficult to compare it 

 with other known types of development; the fact that the follicular 

 cells take a share in the production of the embryo (the process of de- 

 velopment being therefore both sexual and asexual) is not, however, 

 confined to this group. Lankester has described a very similar state of 

 things in Cephalopoda, where the inner capsular membrane, the follicle 

 itself, grows into the ovum and partly forms the nutritive yolk ; recent 

 researches also into the Vertebrata tend to show that the yolk is partly 

 from the cells of the follicle. Sal2)a bicaudata appears to represent the 

 most simple development of all the species, while further complications, 

 such as the formation of a part of the embryo by cells of the oviduct, 

 tend to remove other Saljxv further from the normal mode of develop- 

 ment exhibited in the animal kingdom." {2IittJieil. ZooJ. Stat. Neapel^ IV, 

 pp. 327-102, 6 pi. ; J. R. M. S. (2), iv, pp. 368, 3G9.) 



VERTEBRATES. 



Fish-like vertebrates 



British Fishes.— The work of Dr. Francis Day, on " The Fishes of Great 

 Britain and Ireland," has been lately completed, and in it we have an 

 excellent resume of what is knowu of the finny inhabitants of the home 

 empire. The system and nomenclature as well as definitions of Dr. 

 Giinther are essentially adapted for the generic and supergeneric groups, 

 and a full synonymy and description are given of each species; then 

 follows information respecting the "names," "habits," " means of cap- 

 ture," "baits," "breeding," "life history," "diseases," "uses," "as 

 food," and " habitat " of the species if known or so far as known to the 

 anthor. 



It may be of interest to compare the constitution of the British fauna 

 with that of a limited region of Eastern America, and in the following 

 tables the comparative data are given. The data in the work of Day 

 for the British fishes, and Goode and Bean for the American, as given 

 in "A List of the Fishes of Essex County, including those of Massachu- 

 setts Bay," are accepted for the species. To bring the information to a 

 common denominator, the most recent systematic results of the Ameri- 

 can ichthyologists (who are all in essential accord in this respect) are 

 applied to the snperspecific groups. The data are given (Huder family 

 names adopted by American authors) as to {a) the number of species 

 recorded from (1) Great Britain and (2) Massachusetts Bay, &c., (6) the 

 number of genera represented in (3) Great Britain and (4) Massachu- 

 setts, and (c) the (5) species and (G) genera shared in common by Great 

 Britain and Massachusetts. The Massachusetts region is limited pur- 

 posely in the tables to the waters north of Cape Cod, as the exhibit 

 thus brings out best what are the features common to the two. The 



