Delsman : Fish Eggs and Larvae. 



45 



The under jaw has formed. The gill-cover grows out backwards. 



hi the stage of fig. 8 the rudiments of the dorsal and of the caudal 

 fin begin to appear. The same holds good for the annular constrictions of 

 the gut, which are well developed in fig. Q. These regular constrictions 

 are as characteristic for the larvae of herring- and anchovy-like fishes as 

 is the backward situation of the anus. On the jaws minute teeth appear 

 (the adult Chirocentnis has wel developed teeth). 



Fig, 8. Slightly older larva with rudiment of dorsal fin, length 6,8 mm. 



In fig. 9 the dorsal and the caudal fin have developed further and the 

 anal fin also begins to form. In the caudal fin IQ rays may be counted, 

 a number found in Chirocentnis as well as in Elops. In the dorsal fin I 

 counted 15 rays. For the adult Chirocentrus 1 found 13 large ones + 3 



5> ^nm 



Fig. 9. Larva of 20,5|mm. 



small ones in front, for Elops 24. In the anal fin of the larva 25 rays could 

 be counted, but it was evident that behind these were more forming. In 

 Chirocentnis this number amounts to 26—36, in Elops 15 — 16. Thus the 

 decision between these two forms can no longer be in question : we are 

 undoubtedly dealing with Chirocentrus dorab. 



This conclusion is confirmed by the observation made by me after- 

 wards that on the surface of eggs from the ovary of a full-grown Chiro- 

 centnis the same reticulate design, so characteristic for the pelagic eggs, 

 might be discerned. I have not yet met with larvae longer than 22 mm. 

 We must assume, however, that during further development the forward 



