DISCUSSION OF SPECIES \M> THEIK DISTRIBUTION. 199 



First dorsal (composed of about 20 spines) continuous, extending to the second; Unlets 

 behind the dorsal and anal: a dagger-shaped spine behind the vent. No keel on the tail. 



Caudal fin well developed. Ventrals reduced to a spine each. Seven branchiostegals. 



NEALOTUS TRIPES, Johnson. 



tfealotus tripes, Johnson, Proc. /."•>]. Soc, Lond., 1865, 134.— GUnthek, Challenge! Eeport, \\u, iss7, 35. 



Body very elongate, with a few large, deciduous, simple scales of delicate structure 

 here and there apon its surface. 



The height of the body is contained 9£ limes in its length; the length of the head IA 

 times. Head flattened above, concave in the interorbital region, with four low ridges, the 

 inner pair of which inclose an elongate, diamond-shaped space; lower jaw longest. 



Eye round, lateral, its diameter equal to one-fifth of the length of the head; length of 

 the snout is lij times the diameter of the eye; opercle with two obtuse projections behind, 

 separated by a notch. 



Spinous dorsal inserted in front of the root of the pectoral, its height slightly greater 

 than half that of the body; its length less than halt that of the body; placed in a groove. 

 supported by twenty-one simple slender spines; the second dorsal is placed close behind the 

 first, not SO high and less than half as long, with nineteen rays, and followed by two tinlets. 



The pectoral origin is under the angle of the opercle; its length is equal to that of the 

 second dorsal fin. The spines representing the ventrals are inserted close together under 

 the hinder part of the roots of the pectorals; their length about one-fourth of the height of 

 the body. These spines are longitudinally grooved, and each appears to consist of two or 

 three spines coalesced together. 



Vent very slightly posta edian; a flat, dagger-shaped spine, longitudinally grooved, 

 half as long as the height of the body, inserted close behind the vent. The anal fin is 

 inserted behind this spine at a distance about equal to its length, and is opposite to, but 

 rather shorter than the second dorsal. Caudal fin deeply furcate. 



The lateral line descends obliquely from above the opercle to the middle of the length 

 of the fish, and then continues with a gentler obliquity along the posterior part of the 

 body to the tail, where it is inserted at one-third of the distance from the ventral to the 

 dorsal outline. 



Radial formula: D. xxt | 10 | n; A. IS | III; P. 13; V. 1. 



This species closely resembles Promethichthys atlanticus, from which it may be dis- 

 tinguished by the dagger-shaped spine in front of the anal tin, by the greater number of 

 spines in the first dorsal — -1 instead of IS — by the smaller number in the second dorsal — 

 lit instead of 21 — and by the longer anal, which has IS instead of 16 spines. It also has 

 the ventral spines under the posterior angle of the pectorals, instead of in advance of 

 them, and has iis lateral line descending more gently. 



From Xcsiiirchiis it is distinguished by its ventral fins and by the absence of the car- 

 tilaginous prolongations of the jaws. 



"This fish," remarks (lunther, "was known front a single example, 10 inches long, 

 obtained at Madeira in the month of December, and has been fully described by Johnson. 

 The Challenger collection contains a very young specimen, only 33 millimeters long, which 

 agrees so well with Johnson's description that it no doubt belongs to the same species. ( )nly 

 the dagger-shaped postanal spine is shorter than the ventral spines, and also the separation 

 of distinct Unlets can not be clearly made out, as might be expected in so young an exam- 

 ple. It was brought up in the dredge at Challenger station 10. in lat. 34° 51' X., Ion. 68 

 30' W., where the dredge had reached a depth of 2,675 fathoms. However, no part of the 

 organization of these Trichiuroids indicates that they descend to so great a depth, whilst. 

 on the other hand, young Trichiuroids are not rarely found near the surface. It is, there 

 fore, much more probable that this small lisli entered the dredge shortly before it came to 

 the surface.'' (Giuither.) 



