ATLANT. DEEP-SEA EXPED. 1910. VOL. III]. 



MURAENOID LARVAE. 



17 





Larvae 



Cyema 



atrum 



No. 1 



No. 2 



No. 4 



Preanal segments (vertebrae) 



Postanal — „ — 



45 

 32 



46 

 32 



44 

 31 



42 

 31 



Total 



77 



78 



75 



73 



Leptocephali or Eel. On these points we cannot doubt 

 the connection between the larvae in question and Cyema 

 atrum. 



The following table contains some further measure- 

 ments of the four larvae: 



the beginning of a retrograde metamorphosis is that the 

 anterior portion of the body is not quite so high as in 

 no. 1. All the fins have rays, H 1 and H 2 of the caudal 

 fin having six rays each. I was able to count 24 teeth 

 in the upper jaw and 20 in the lower jaw. The pig- 

 mentation of both specimens is alike, except that the 

 series of dots along the lateral line extends farther for- 

 ward in no. 2. The anus is placed far back and there 

 are 123 preanal and 33 postanal segments, 156 in all. 

 Specimen no. 3 is 126 mm long, and attains its 

 greatest height of 13 mm about 85 mm from the point 

 of the snout. This specimen has reached its full devel- 

 opment as a larva, and has rays in all the fins, the caudal 

 fin having 11 rays: H t five, and H 2 six. There are 125 



No. l 



No. 2 



No. 3 1 ) 



No. 4 2 ) 



Total length 



Greatest height 



Distance between point of snout and anus 



„ „ „ first dorsal interspinous element 



„ anterior margin of the eye 



Length of the head 



Diameter of the eye 



47 mm 



24 „ 



32.5 „ 



33.5 „ 



3.6 „ 



5.5 „ 



1.0 „ 



47.5 mm 



24 „ 



33 , 



33 „ 



3.9 „ 



5.7 „ 



1.0 „ 



48 mm 



23 „ 



33.5 „ 



33.5 „ 



4.1 . 



5.9 . 



1.0 „ 



54 mm 



25 „ 



39 „ 



40 „ 

 ? 



? „ 

 1.1 „ 



5. Leptocephalus Congri vulgaris. 



L. Morrisii. 



Three spesimens were taken of this species. 



Specimen no. 1 is 84 mm long, with a maximum 

 height of 8 mm. It is a fully developed, though not 

 full-grown larva, having 124 preanal and 35 postanal 

 segments, 159 in all. The anus is situated far back, 11 

 mm from the tip of the tail. The snout is pointed and 

 the nostrils well separated the anterior one tubular, 

 directed forward and a little upward, whereas the post- 

 erior one is a roundish aperture. It has many teeth, about 

 25 in each half of the upper jaw, and about 20 in each half 

 of the lower jaw. Strong rays are present in all the fins, 

 the caudal fin having 12 rays, of which H x has five and 

 H 2 seven. 



As for pigment there is a series of starshaped spots 

 along the upper edge of the alimentary canal, spots at 

 the bases of the rays of the anal and caudal fins, and a 

 series along the lateral line of the postanal segments. 



Specimen no. 2 is 102 mm long, having a maximum 

 height of 9 mm, and is in nearly the same developmen- 

 tal stage as no. 2. They only feature possibly indicating 



preanal and 30 postanal segments, 155 altogether. In one 

 half of the upper jaw I counted 29 teeth, and in half of 

 the lower jaw 20. The snout is pointed. Nostrils and 

 pigment as in no. 1. The following table gives the stations 

 and depths from which the specimens was taken:— 



No. 



Length 



Station 



Date 



Depth 



1 



84 mm 



10 



19/ 4 _21/ 4 



150 m 



2 



102 „ 



42 



23/. 24/ 5 



150 „ 



2 



126 „ 



92 



23 /7 _ 2 4/ 7 



500 „ 



No.s 1 and 3 were taken where the depth exceeds 

 3000 metres, while no. 2 was taken near the coast of 

 Morocco where the depth is less than 2000 metres. If 

 we compare the length of the specimens with the date 

 of capture we see that the length increases from spring 

 to autumn, but the material is too scanty to determine 

 whether this denotes the growth of the larvae, or is only 

 accidental. 



Compared with these three larvae the larvae described 

 by Schmidt are on the whole larger. The facts that our 



') Tip of tail has disappeared, and the numbers are therefore approximate. 

 2 ) Point of snout somewhat damaged ... 



