42 A, H. HEFFORD. 



they are absent from here in the two smaller eggs. Although pre- 

 cautions were taken to keep the temperature low by standing the jars 

 containing ova in circulating tank-water, the eggs became infested by 

 infusoria, whose presence is a usual accompaniment to unhealthy con- 

 ditions. Development proceeded apace, however, and the next day the 

 free caudal region had grown around the yolk, so as to almost meet the 

 head. The bright yellow pigment of the embryo is now visible to the 

 naked eye. It occurs in large dendritic chromatophores, which ramify 

 and intermingle so as to produce a diffuse colouration over the whole of 

 thepre-anal part of the trunk, and appears especially dense about the anus. 

 There is a further band-like mass of yellow about the mid-post-anal 

 region, and an aggregation of similar chromatophores on the yolk-sac, 

 between the oil-globule and its posterior contour. In one specimen 

 (diameter "82 mm.) the oil-globule, at this stage, has a dark and smoky 

 appearance, and is densely pigmented. In another specimen no pigment 

 is seen over the oil-globule, and the periblastic pellicle, which is gener- 

 ally quite apparent at this stage, showing an interspace between it and 

 the contained oil-globule, is not distinguishable. The epidermis of 

 embryo and yolk-sac is covered with tiny tubercles, doubtless of patho- 

 logical origin. Next day the larva had hatched out but was distinctly 

 moribund, and died almost immediately. The total length is 216 mm., 

 and it measures 100 mm. from snout to anus. The head projects 

 rather considerably over the oval-shaped yolk-sac. In two of my larvae 

 the oil-globule was almost in the centre of the yolk-sac, which was 

 observed by Heincke and Ehrenbaum to be the case only in one instance, 

 and may be regarded, therefore, as an abnormal and possibly patho- 

 logical condition. The small otocysts are situated some distance behind 

 the eyes. There is a slight swelling in the tubular gut above the 

 pectoral region and the rectum ends blindly immediately behind the 

 postero-dorsal edge of the yolk-sac. The pigmentation, which is on a 

 generous scale, is very characteristic. Inter-ramifying yellow chroma- 

 tophores form a diffuse mass of colour over the posterior part of the 

 yolk-sac, and practically over the whole of the pre-anal part of the 

 trunk and head, extending a little beyond the anus. Then comes a 

 clear space followed by a band of yellow somewhat behind the mid-post- 

 anal point. The much less conspicuous black pigment in small 

 chromatophores which when relaxed show fine dendritic outgrowths, 

 occurs chiefly on the dorsum in the pre-anal region and, less densely, on 

 the head and sides. Post-anally there are about half a dozen chromato- 

 phores along each of the dorsal and ventral contours, extending further 

 posteriorly than the yellow pigment, although the extreme end of the 

 tail is pigmentless for about "25 mm. Black chromatoi)hores are 



