264 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



functional development of the claspers. Its teeth are represented by Figs. 6 

 and 7 on Plate 5 of the present work. In ii umber of plates and their general 

 outlines these teeth are somewhat like those of a young Chimaera, but in 

 regard to the tritoral surfaces they are very different. On the palatine and 

 the mandibular teeth there are prominent series of tritors, like small rounded 

 molars ; on each of the palatines a series appears, the next to the outer, in 

 which the tritors from the third counting backward are broadened into trans- 

 verse bars, or in which two small tritors, or more, have United into one bro;id 

 one. On each jjalatine tooth there are four more or less comj)lete series of 

 the tritors, the outer two or three of which are extended farthest backward. 

 On the outer edge of each mandibuLir tooth there is a series of about ten of 

 the tritors or cusps, and from the sixtli and the seventh two shorter series 

 extend back nearly parallel with the inner edge of the tooth. The vomerine 

 teeth resemble in outline those of Chimaera. Medially in front each hooks 

 downward in a sharp point ; laterally from the point the edge lies higher and 

 has three rounded tritors, the hindmost of which forms the hinder edore of the 

 tooth. The claspers are but partially developed ; they are short, without 

 spines, stout and muscular at the bases, and in the distal three fifths of the 

 length are slender, cylindrical, and rounded. The groove is distinct to the 

 end. Tlie positions of the ventral tenacula are indicated by the openings, but 

 within the tenacular cavities the organs are (juite undeveloped ; the spines, of 

 course, are entirely absent. The frontal tenaculum, being of later develop- 

 ment than the claspers, is not yet differentiated. Though there appears to be 

 nothing on the sides of the forehead of this individual to distinguish it from a 

 female, if looked at from above the shape of the tenaculum appears to be 

 faintly outlined beneath the skin in its proper position. The dorsal spine has 

 a sharp compressed keel on its front edge ; it is triangular in a cross-section ; 

 each of the hinder edges turns directly outward at the side, is sharp, and is 

 barbed by sharp teeth hooking toward the base of the spine. At each side of 

 the postorbital space on the crown there are three or four spines in irregular 

 series, and there are four in longitudinal series at each side of the anterior 

 portion of the base of the second dorsal. The upper margin of the third 

 dorsal is like the others and has no such armature as that of Rhinochimaera 

 2)acifica (Plate 4, Fig. 2). 



The lateral line system resembles that figured on Plate 2, Figs. 3-5, from 

 specimen 39415, but shows individual variation in several points. The upper 

 rostral tract meets the lower at a short distance behind the tip of the snout ; 

 they pass into one another at each side of the rostrum. Behind the transverse 

 band of sensory papillae or villi, on the left side of the lower surface of the 

 snout the subrostral line extends back between the suborbital and the prenarial, 

 but does not join with the latter like its fellow of the other side, and the pre- 

 narial does not curve out to meet it. Behind the mouth on the chin the line 

 is broken into dashes instead of being entire and transverse; similarly on the 

 throat the transverse line is broken more or less, and is discontinued for a short 

 distance about the middle. Below the middle of the supracaudal fin the lateral 



