458 Holt — On the Eggs and Larvce of Teleosteans. 



greatest width is in front of the mid-brain ; and the posterior limit is about the 

 level of the crystalline lens. Ventrally it is dilated below the free part of the 

 mid-brain, the inferior contour running from a point a little above the cerebral 

 lobes to the top of the eye. A short median fold is directed downwards in front 

 of the pineal region. The heart {h.) is large and active. Its hind end rests 

 against the yolk (y.), which is reduced and j^yriform, anteriorly blunt, and 

 still exhibits very clearl}- the ovoidal peripheral segments [c. v.) The smaller 

 oil-globules have disappeared ; the larger ones are scattered over the general 

 yolk-surface, principally at the posterior end. A few largish ones at the front of 

 the yolk very probably represent the coalesced smaller globules. 



The jiectoral fin (p-f-) is fairly large, but as yet simple ; it lies on the dorsal 

 wall of the abdomen, with obliquely rotated base, a little behind the level of the 

 front of the yolk mass. The gut is large and perforate except at the anus. It is 

 bent down in the middle of its length, just in front of which point occurs a large 

 dextral sac (5. ) apparently representing the cardiac dilatation of the stomach. Pos- 

 teriorly the rectum (r.) descends obliquely towards the edge of the marginal fin, 

 which the imperforate anus does not quite reach. The long narrow urocyst (ii.) 

 lies against the posterior wall of the rectum. The notochord is multi-columnar 

 with largish cells, and is rather stout. From the pre-cranial vesicle (/.) the dorsal 

 marginal fin rises in a gentle ascending curve till it reaches a point a little 

 behind the pectorals, where its height is '48 ram., the total heiglit of body with 

 yolk and fin being 1 '08 mm. Thence the fin descends gradually to the broad 

 rounded caudal lobe, in which embryonic fin rays have appeared. The ventral fin 

 has about the same dimensions as that part of the dorsal which is opposite to it. 

 Just behind the anus the trunk is about "24, whilst the dorsal and ventral fins are 

 each about "39 mm. in height. The pre-anal fin, extending nearly half-way along 

 the yolk, is somewhat broader. The anterior three-quarters of the head and trunk 

 is covered with profuse dendritic pigment of a bright gaml)oge-yellow colour ; 

 there is a very bright patch [p. b.) at the end of this region, from which ramifica- 

 tions extend on to the dorsal and ventral fins, anastomosing with a large chromato- 

 phore on each fin. The rest of the trunk is little pigmented. Round yellow 

 chromatophores are distributed over the general surface of the yolk-sac, dendritic 

 pigment covers the pre-cranial vesicle and pre-anal fins, and there are six and four 

 large patches along the margins of the dorsal and ventral fins respectively. 



A few small stellate black chromatophores occur on the fore- and mid-brain, 

 about the commencement of the notochord, over the yolk-sac and along the ventral 

 edge of the hinder third of the gut. Black pigment also occurs in faint lines 

 along the sides of the pre-cranial vesicle. No black pigment occurs on the eye. 



I cannot say anything definite as to the age of this larva, except that it is more 

 than six hours old. 



