106 MR J. T. CUNNINGHAM ON THE 



posterior end of the embryo. Some of the eggs were hatched, and fig. 4 shows 

 the form of the larva immediately after hatching ; the length is 21 mm. ; the 

 notochord, as seen in fig. 4a, is mnlticolnmnar ; there are black pigment spots 

 on the body, but the eye is unpigmented ; the pigment on the post-vitelline 

 part of the body forms two black transverse bands. The intestine was, I believe, 

 not open, but a solid extension of it extended to the ventral edge of the larval fin. 



In a great many respects the present species agrees with Motella mustela, 

 Linn., as described by George Brook,* from eggs actually observed to be 

 deposited by the parent. There are several minute points of difference. 

 Brook's measurement of the ovum is '655 to - 731 mm. in largest diameter, 

 while he gives the length of the newly hatched larva as 2 - 25 mm. ; thus the 

 diameter of the ovum given by Brook is slightly less than my measurement, 

 while the length of the larva given by him is slightly greater than what I have 

 stated. The position of the oil globule and rectum is also different in my 

 figure from that in Brook's. But the points of agreement are more numerous 

 and important than the points of difference ; the arrangement of the pigment, 

 for instance, is exactly the same in the two accounts. It is evident, therefore, 

 that the species I have described is either Motella mustela, Linn., or some other 

 of the four British species of Motella. 



Pelagic eggs closely similar to the species here described, and to those of 

 Motella mustela as described by Brook, have been described by A. Agassiz and 

 C. O. Whitman^ and referred with some uncertainty to Motella argentca, 

 Rhein. Two other species of pelagic eggs have also been provisionally ascribed 

 by those authors to the genus Motella. 



Species No. 14 (PI. VII. figs. 5, 6). 



This form is well characterised ; it possesses one feature which, as far as 

 extant observations show, is present in no other pelagic ovum, namely, that the 

 yolk is divided into a number of polyhedral masses. This egg is the most 

 perfectly pellucid of all I have observed, and the planes of division in the yolk 

 appear in optical section as extremely fine lines. The egg is slightly oval in 

 shape, '94 mm. by -97 mm. in diameter. The newly hatched larva is 363 mm. 

 in length, the notochord is unicolumnar, and the anus is separated from the 

 yolk by two-thirds of the length of the post-vitelline part of the body, as in the 

 herring ; the larva is absolutely without pigment. The eggs were obtained in 

 1884 and 1886, in the latter end of May and during June. In each season 

 they were taken within the Firth of Forth, between Gullane Ness and 

 tin; island of Inchkcith. This form, from its conspicuous characteristics, has 



* Linn. Soc. Jour., vol. xviii. 



t '' Pelagic Stages of Young Fishes," Memoirs of Mas. Comp. Zool. Harv., vol. xiv., No. 1. 



