350 
Part III. — Ninth Annual Report 
stratum resembling the * zona esterna vesicolare ' seen hy Eaffaele in 
C. festivuSj and recalling the segments in the yolk-surface of the sole. 
Lines of division crossed over the yolk either in curved or variable broken 
courses, often crossing or running into each other, and the surface had 
thus the appearance of incomplete and irregular segmentation. In profile 
the pseudo-segments protruded in the form of depressed mounds, with 
their rounded apices directed inwards. The entire surface of the yolk 
showed this ill-defined vesicular character, but its outer contour was 
unbroken and smooth, and the perivitelline space was somewhat large. 
Pigment was present of a rich yellow colour, deeper than canary yellow, 
and approaching an orange tint. It occurred as small grains upon the 
head, before and behind the eyes, and dispersed in this anterior region 
beyond the embryonic trunk proper over the yolk, but to a very limited 
extent. A girdle of amorphous yellow spots occurred just in front of 
Kupffer's vesicle, and others were grouped at the caudal end of the fish 
(see Plate XIII. fig. 11). In a more advanced ovum (Plate XIII. fig. 10) 
black pigment spots had made their appearance. They occurred sparsely 
upon the trunk, but were absent from the pre-otocystic area, while some 
occurred in the girdle of yellow spots and the posterior band, now well 
defined and situated slightly anterior to the termination of the tail. 
Minute black granules, very few in number, occurred beyond the trunk 
along each side. The yellow spots were now more scattered, and, in 
addition to the two caudal bands, they were scattered irregularly over the 
head and mid-trunk, and extended over the surface of the yolk, not, how- 
ever, beyond the hemisphere on which the embryo rested. The more 
distal half of the yolk was quite destitute of pigment. The occurrence of 
black pigment in the embryo before hatching is noteworthy. Mr Holt's 
figures show yellow pigment only, and certainly C. festivus^ according to 
the description and drawings of Raffaele, exhibits yellow coloration only ; 
but black pigment appears at an early stage in C. lyra. The larva, on 
emerging, showed considerable opacity ; the yolk, though the pseudo- 
segments are not discernible, exhibits striations and irregularities over the 
surface, while the body and embryonic fin-membranes are very uneven 
and covered with granular projections, not apparently due to an unhealthy 
condition. 
When forty-eight hours old the free embryo has lengthened, the snout 
is pointed and unusually prominent, the branchial clefts (two pairs) at 
this stage are indicated, and the pectoral fins are most marked (Plate XIII. 
fig. 12). These last structures form rounded pad-like areas some little 
distance from the trunk proper, and midway between the eyes and the 
anus, a position very unusual — the fins in many species appearing much 
nearer the head. Irregular streaks of yellow pass round the fins, and 
give them great definiteness, while yellow spots of a variable complicated 
form occur on the snout around the eyes and otocysts, and along the sides 
of the trunk. The yellow pigment is still largely confined to the upper 
half of the yolk, and the sparse black spots are strictly so confined, save 
for those on the trunk, and especially in the two caudal bands. From the 
head black spots are almost absent, one only appearing on the anterior 
surface of each eye. The three yellow patches in the median embryonic 
fin occur as in Mr Holt's figure, but the fin rose much higher dorsally, 
imparting a hump-backed appearance to the fish. The shape of the yolk, 
too, was more elegantly ovate in form, and the anal strand passing from 
the rectum to the ventral edge of the embryonic membrane is coloured with 
yellow spots (Plate XIII. fig. 13). Embryos were not studied at later stages 
than the second day after extrusion from the ovum, and up to that time 
the black pigment exhibited the form merely of minute grains or points pf 
