28 A. E. HEFFORD. 



Zeugopterus punctatus (Bl.). 



Before the outgrowth of the caudal rudiment, the body of the 

 embryo is beset with fine, black chromatophores which are chiefly, if not, 

 entirely, on the dorsal surface. A few black chromatophores of 

 larger size are found over the oil-globule, and there may be a small 

 number of black spots on the yolk-sac, which is beset with a moderate 

 number of roundish, yellow chromatophores. The latter pigment 

 occurs in smaller spots on the liead and body of the embryo. At this 

 stage the perivitelline space is somewhat large, and the oil-globule is 

 contained in a very distinct periblastic pellicle. 



With the growth of the free caudal region (Fig. 2) a marked increase 

 in the size and number of chromatophores takes place. The yellow 

 spots over the yolk-sac now acquire a stellate form, but on the 

 embryo they still occur as patches disposed over the head and body. 

 Yellow does not extend quite to the tip of the caudal extremity as the 

 black does. The black chromatophores over the oil- globule have 

 increased in number, and are the largest of all. Over the yolk-sac 

 they are small and sparingly scattered. Minute black specks occur 

 over the whole body, from anterior to posterior extremity, being most 

 concentrated along tlie dorsal and ventral contours, dendritic out- 

 growths from which extend to the embryonic fin. The pectoral fins are 

 relatively well developed, and rudiments of the pelvic fins are visible. 



Three larvae observed soon after hatching (Fig. 9) had lengths of 

 2"90, 292, and 29o mm., the pre-anal lengths being respectively 1'44, 

 1*40, and 1"45 mm. The anus is therefore appreciably nearer the 

 median position than in the case of Zeugopterus norvegicus, which 

 otherwise it very closely resembles both in general form and in the 

 distribution of its black and yellow pigmentation, the former occurring 

 in mostly small, fine specks and the latter in large, stellate chromato- 

 phores. The yolk-sac is elongate and bears the much-reduced oil- 

 globule at its posterior end. As in the above species, the marginal 

 pigment of the unpaired fins is of most diagnostic importance. Im- 

 mediately after hatching I found some resemblance to the arrangement 

 in Z. norvegicfis, but the " fringe " formation is not so well marked, 

 and within one day a striking change has taken place which appears 

 to be quite characteristic of Z. imnctcdus, at least as distinct from 

 Z. norvegicus. I can, of course, make no comparison with Z. himacidatus, 

 though it is to be noted that Holt's newly hatched larva from an arti- 

 ficially fertilized egg of Z. himaculatus showed no fringe-like occurrence 

 of pigment along the upper and lower margins of the unpaired fins, 

 which I observed in my larvae of both species. 



