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



MURAENOID LARVAE. 



25 



12. Leptocephalus enchodon n. sp. 



This species, of which one specimen was taken at 

 Stat. 62 in 150 metres, somewhat resembles a larva of 

 Conger vulgaris, among other things in having 158 seg- 

 ments (112 preanal and 46 postanal), but other characters 

 clearly prove it to be distinct. 



It is 108 mm long and as shown in fig. 3 on pi. 

 IV it is rather high (13 mm), terminating posteriorly in 



^^5 



Fig. 20. Head of L. enchodon. 10 /i. 



a point. The head is inclined downwards, so that the 

 greater part of it falls below the level of the median line, 

 which runs midway between the dorsal and ventral margins 

 of the animal. The snout is short, but pointed, profile 

 curved. Upper jaw protrudes a little in front of the lower 

 jaw. There are 20 teeth in each half of the upper jaw, 

 the foremost one being at some distance from the suc- 

 ceeding ones, which form a continuous row. Each half 

 of the lower jaw contains 17 teeth, the foremost of which 

 is very peculiar in form as shown in fig. 20. 



The nostrils are quite separated, the anterior one 

 being semitubular, whereas the posterior one, situated in 

 front of the eye, is an oval aperture (see fig. 20). 



The first traces of true rays may be seen in the upper 

 two-thirds of the pectoral fin, the lower third having 

 retained its embryonic character. The vertical fins and 

 the caudal fin contain powerful rays. The caudal fin has 

 10 very long rays (2 mm), H t and H 2 having five each. 

 The hindmost rays of the vertical fins are placed close up 

 to the caudal fin-rays. Anus is placed far back, 18 mm 

 from the tip of tail. 



The alimentary canal is thin and runs along the 

 ventral margin of the animal. Throughout nearly its 

 whole length there is an interspace between it and the 

 ventral margin of the muscle-segments. 



The pigmentation is characteristic. Along the canal 

 there is a series of elongated spots, continued by a series 



of smaller rounded spots on the anterior interspinous 

 elements of the anal fin. Pigment is dispersed in thin 

 stripes on the anal and caudal fin-rays, as well as on the 

 posterior dorsal fin-rays, most strongly developed at the 

 bases. Over the ventral part of the muscle-segments, a 

 little below the lateral line, there are pigment spots in an 

 irregular zig-zagline from the 14th segment to near the 

 tip of the tail. There are also two spots directly in front 

 of the curvature of the alimentary canal below the pectoral 

 fin (see fig. 20). 



13. Leptocephalus euryurus n. sp. 



The "Michael Sars" procured two" larvae of this spe- 

 cies, representing somewhat different stages of develop- 

 ment. The one from Stat. 34, between 200 and 500 

 metres, near the coast of Morocco, is 46 mm long, with 

 a maximum height of about 6 mm. Fig. 4 on pi. IV 

 reproduces a photograph of this species, which is of nearly 

 uniform height, the dorsal margin of the body being 

 almost continuous with the upper contour of the head, 

 and the tail being rounded. 



The segments 58 preanal, and 58 postanal, 116 in all 

 are of the usual shape. The anus is placed almost exactly 

 midway between the point of the snout and the tip of 

 the tail. The head is short and high, measuring 2-7 mm 

 from the point to the anterior edge of the first complete 

 muscle-segment, with a maximum height of 2-2 mm. 



The snout is short, but quite pointed, measuring 1 

 mm from the point of the snout to the anterior margin of 

 the eye, which is small (maximum diameter 0-5 mm), and 

 not quite round, having undulations on the upper and 

 lower edges (see fig. 21); the right eye, with only one 

 undulation on the upper edge, is placed nearer the jaw 

 than the upper contour of the head, and the lens is 

 quite small. 



The nostrils are separated, the anterior one being placed 

 almost midway between the anterior limit of the brain 

 and the point of the snout, and is an oval aperture, while 

 the posterior one is smaller and nearly round, and placed 

 higher than the eye. The brain extends forward beyond 

 the anterior contour of the lens of the eye, and does not fill 

 the space between the eye and the upper margin of the head. 



The teeth are quite powerful. The foremost teeth 

 in each jaw are broken off in this specimen, but judging 

 by those in the second specimen (represented in fig. 22) 

 they are probably curved, while the succeeding teeth are 

 conical, 8 in the upper jaw, 9 in the lower jaw, dimi- 

 nishing in size backwards. 



The gill-opening is a very small slit placed laterally, 

 directly behind the curve of the alimentary canal where 

 the body joins the head. 



