Dr. Cantor on the Fetus of Zygzena laticeps. 373 
seldom seen, and attains to about eleven feet in length, and 
Z. laticeps, which is exceedingly numerous, and apparently of 
smaller size than the former. On the 15th of September 1844, 
some Chinese fishermen captured off Prince of Wales Island a 
gravid female Z. laticeps, by far the largest which has come under 
my observation, of the following dimensions :— 
Entire length of the fish ............ssscsceees . 4ft. 4in. 
Breadth of the head (the anterior margin)... 2 ft. 1} in. 
On being opened there appeared eighteen living young ones, 
of which number seven were males, distinguishable by the anal 
appendages, and eleven females. All eighteen were of nearly 
equal size, and of the followimg dimensions :— 
Entire length of the body .........ccccecessccseceees 1 ft. 13 in. 
Breadth of the head (anterior margin) ............ 6 in. 
The relative proportions of the head and body consequently re- 
main nearly the same in every stage of growth. The lateral pro- 
cesses of the head were in the foetus considerably bent in a back- 
ward and inward direction, imparting to the head the shape of a 
broad arrow, whereas these processes after birth form with the 
body a right angle, which makes the fish resemble a double ham- 
mer, or the letter T. In the foetus the lateral processes are en- 
tirely membranous, except a narrow cartilaginous cylinder which 
encases the optic nerves, and which is so pliable that it does not 
prevent each lateral process from lying in close contact with the 
sides of the body, and thus they take up but comparatively small 
room, and offer no obstacle under parturition. None of the foetuses 
were provided with branchial filaments. The teeth, in the adult 
fishes comparatively small, were barely perceptible to the touch. 
The colours were pr ecisely similar to those of the adult. Zygena 
laticeps in its foetal state, and shortly after birth, answers in every 
respect to the description, and resembles so exactly the deli- 
neation of Z. Blochi, represented by M. Valenciennes, Mém. 
du Mus. ix., that i all probability the original of Bloch, pl. 117, 
and of M. Valenciennes, which has afterwards been copied by 
myself and lately by Mr. Yarrell, was a foetus or very young spe- 
cimen of Z. laticeps. As neither Bloch nor M. Valenciennes ap- 
pear to have given the dimensions of the fish figured, it is impos- 
sible to decide the question till the actual size of their original 
has been ascertamed. The smallest specimen which I have ob- 
served of Z. daticeps in its perfect state—I mean in which the 
lateral processes of the head form a right angle with the body— 
measured 13 ft. in total length. From this I infer, that the 
lateral processes of the head, which in the foetus branch off from 
the head under a sharp angle, pomting backwards, change their 
position and acquire firmness at no remote period from the birth. 
