28 



EINAR LEA 



[REP. OF THE "MICHAEL SARS" NORTH 



V as faint shadows. There are also three spots on the 

 surface of the body forming a triangle: one spot on the 

 lateral line and the other two near the ventral margin of 

 the muscle-segments. 



On either side of the alimentary canal we find 13 oval 

 double-spots. Between its first and second and between 

 the second and third pairs of spots there is a single spot 

 on the ventral margin. 



The pigmentation of the head is shown in fig 25. 

 We see the pigment at the base of the proboscis, near 

 the point of the lower jaw, two spots on the brain-portion, 

 and one spot on the alimentary canal directly under the 

 pectoral fin. An extremely fine pigmented line, consisting 

 of about twenty minute dots, runs backwards from the 

 spot under the pectoral fin towards the first spot on the 

 alimentary canal. 



The form and position of the nostrils are characteristic. 

 They are both at quite a distance from the eye, and the 

 anterior one looks as if it might become a narrow horizontal 

 cleft, whereas the posterior one is an oval aperture; they 

 are not yet fully separated. 



The dentition is rather peculiar. Each half of the 

 upper jaw is furnished with a curved tooth anteriorly 

 directed obliquely forward; it is followed by 4 short thick 

 conical teeth directed downward and then 6 small sloping 

 teeth. Each half of the lower jaw is likewise furnished 

 with a curved tooth anteriorly, followed by 7 large teeth, 

 and 8 small sloping ones. 



The single specimen has a damaged tail, so that it 

 is impossible to ascertain the length, the number of 

 segments, and the form and development of the caudal 

 fin. In its present state it measures 55 mm from the base 

 of the. foremost tooth of the upper jaw to the tip of 

 the broken off body, and there are 75 preanal and 41 

 postanal segments, so that it must have had more than 

 116 segments altogether. 



From point of snout (proboscis not included) to 

 anus it measures 37 mm, length of head (from base of 

 proboscis) 4-4 mm, length of snout 1-7 mm, and greatest 

 diameter of the eye 1-1 mm. 



All the fins In the damaged individual show no 

 trace of rays; the vertical fins seem to lack interspinous 

 elements too. 



As far as I am aware, only one species with its snout 

 produced into a proboscis has hitherto been described, viz. 

 L. rostratus Schmidt. The larva in question is undoubtedly 

 distinct from L. rostratus, which has about 190 segments 

 (a number which our larva can never have possessed); 

 but that they are closely allied is proved by the presence 

 of a proboscis, the position of nostrils far removed from 

 the eye, the telescopic eyes, and the pigmentation of the 

 alimentary canal. 



16. Leptocephalus dolichorhynchus 11. sp. 



Three specimens of a species very closely allied to 

 L. proboscideus were taken by the "Michael Sars": two 

 small ones at Stat. 67 in the net at 100 metres, and a large 

 one at Stat. 53 in the net at 150 metres. Fig. 2, pi. V is 

 a reproduction from a photograph of the largest specimen, 

 and shows the peculiar aspect of these larvae distinctly; a 

 comparison between this figure and fig. 1 pi. V brings 

 out the resemblances and differences between this form 

 and L. proboscideus. It is quite evident that these two 

 forms are closely allied, and may be grouped together 

 with L. rostratus described by Schmidt (27). This group 

 is distinguished from other leptocephalids by the point 

 of the snout being elongated into a proboscis, by the eye 

 being telescopic, and by the nostrils being placed far 

 forward on the snout. 



Before proceeding to describe the three larvae, the 

 characters that seem to justify us in regarding them as 

 representing a new species may be enumerated. 



The number of segments varies between 128 and 136, 

 thus readily distinguishing these larvae from L. rostratus, 

 which has about 190 segments. A comparison with the 

 larva described as L. proboscideus is in this respect 

 impossible, because the number of segments could not 

 be determined owing to the defective condition of the 

 single specimen. A striking difference is found in the 

 pigmentation of the musculature of the body, the arrange- 

 ment of which in L. dolichorhynchus is shown in fig. 2, 

 pi. V, this arrangement being identical in the three larvae. 



We see that in L. dolichorhynchus in contrast to L. 

 proboscideus the two spots at the ventral margin of the 

 musculature, as well as a third elongated spot on the 

 lateral line above the other two, are wanting. Figs. 2 

 and 3, pi. V also prove how different is the arrangement 

 of the pigment of the lateral line in the two species; for 

 whereas L. proboscideus exhibits spots far beneath the 

 surface and, for the greater part, on the anterior half of 

 the animal, L. dolichorhynchus has five spots lying at the 

 surface of the animal and, for the greater part, on its 

 posterior portion. 



There is also a difference in the pigmentation of the 

 alimentary canal, L. proboscideus being provided with 

 longitudinal chromatophores arranged in two series on 

 either side of the alimentary canal, while the pigment in 

 L. dolichorhynchus is arranged in a manner most easily 

 seen from the ventral side: proceeding backward from the 

 head, we find first a chromatophore just under the pectoral 

 fin (figs. 26 and 27), then a spot on each side of the 

 anterior narrow portion of the alimentary canal (one of 

 these spots is shown in fig. 2 pi. V); farther back, on the 

 expanded portion of the alimentary canal, there are seven 



