Holt — On the Eggs and Larvce of Teleosieans. 443 



its length. Its thickened region fails to reach the hinder end of the yolk, and 

 terminates in a conical process, from which the narrow cord-like rectum (r.) passes 

 down along the posterior of the yolk sac to the marginal imperforate anus (a.). 



The marginal fins (fig. 41) are of moderate size, and about equal in height with 

 the free caudal region of the trunk. The dorsal commences behind the otocysts (o^.), 

 the caudal is short and rounded, and the ventral sends forward a narrow strip 

 along the postero-ventral border of the yolk sac {y. s.). 



The notochord [no. ) is unicolumnar throughout ; the cells do not show the same 

 ampullation as in the herring, &c. The pectorals have not appeared. The pig- 

 ment is a bright orange, dark by transmitted light. It occurs in a conspicuous 

 patch on the snout. There is a well-marked bar [p. b.) extending into the dorsal 

 fin, across the middle of the free caudal region of the trunk, an arrangement 

 common to many larval fishes. In front of this, two lines of round chromatophores, 

 dorsal and ventral, run forward along the sides to the cephalic region, the dorsal 

 line extending on the top of the midbrain. Similar chromatophores are scattered 

 over tlie posterior moiety of the yolk sac, and a few occur on the edge of the 

 ventral fin near its commencement. 



Two large pigment patches occur on the edge of the anterior half of the dorsal 

 fin, and there are a number of small chromatophores along the bases of the dorsal 

 and ventral fins about the posterior extremity of the body.* 



The newly-hatched larva, whilst presenting resemblances to that of C. festivus 

 (see Raffaele, op. cit., p. 33) in the character of the pigment and the large size of 

 the yolk, differs from that form in the possession of a well-developed heart at the 

 time of extrusion. 



Raffaele says nothing definite as to the dimensions of the larva ("piccola"), 

 nor does he allude to the structure of the notochord in the Mediterranean species. 

 From his figure of the newly-hatched larva, it is evident that the rectum is even 

 at that stage separated from the yolk. 



I cannot say anything as to the time the Qgg of C. lyra takes to develop. 

 In the specimens described above the embryo was considerably advanced when 

 taken on the eveiiing of the 20th June, and hatched on the following day. The 

 faint striae noticed on the yolk surface in the larva may have some relationship to 

 the vesicular layer of the yolk of C. festivus, though it is remarkable that, if any 

 trace of such a structure exists in C. lyra, neither M'lntoshf and Prince or 

 Cunningham should have detected it in the ova. I certainly saw nothing of the 

 sort in any of the ova that came under my notice. 



* "Whilst imder observation minute tubercles made tlieu- appearance all over the integument of this 

 specimen (as shown in figure 41). Death ensued shortly afterwards. 



\ The ovum of this species was first described by Professor M'Intosh in the Ann. and Mag. Nat. Hist. 

 Dec. 1885. 



TEANS. KOr. DUB. SOC, N.S. VOL. IV., PAET. VII. 3 R 



