BY J. DOUGLAS OGILBY. 401 



front, the anterior cusp being rather stronger than the basal pair; 

 mandibular plate with nine cusps, the last but one (rarely the last 

 two) on each side much enlarged, the median one generally so ; 

 the discal dentition consists of three strong teeth anteriorly, the 

 basal pair being on a line with the inner borders of the maxillary 

 plates; they are similar in shape and arrangement to each triad 

 of maxillary cusps, but differ in being entirely disconnected, 

 though contiguous, at their bases; behind these a series of broad 

 sharply-ridged lamellae extends backwards along the sides of the 

 disk close to the gular cavity and is continued behind the mandi- 

 bular plate; each lamella is furnished with a strong cusp near its 

 inner extremity and a smaller one at its outer, the lateral ones 

 having a supplementary cusp outside and partially behind the 

 inner cusp; between the discal lamellae and the rim of the disk 

 there is a row of small, sharp, hooked teeth ; tongue with two 

 narrow elongate plates arranged along each side of its dorsal 

 aspect; the anterior pair are almost parallel, the distal extremity, 

 however, being curved outwards and backwai'ds, and armed with 

 seven or eight line subequal cusps and an enlarged terminal cusp, 

 while on the linear portion seven cusps are present, the middle 

 ones being the longest and the terminal one small; the posterior 

 and outer pair of plates are inserted obliquely, with the convergent 

 ends in front and in contact with the middle of the base of 

 the inner plates; each is furnished with from twelve to fourteen 

 fine cusps, which gradually decrease in size from the front ; the 

 ventral surface is armed at the base with a deep, transverse, 

 V-shaped plate, the apex of which is radical ; the outer border of 

 each limb forms a deep concavity, which terminates in a stout, 

 hookel cusp, outside the base of which the plate is curved 

 inwards and backwards, both the recurved portion and the limb 

 itself being armed with comb-like cusps, two or three of which 

 on either side of the apex, are somewhat enlarged. The vent is 

 situated beneath or a little in advance of the commencement of the 

 last third of the second dorsal fin ; the length of the tail is 6| to 

 74 in the total length. The distance between the origin of the 

 dorsal fin and the tip of the tail is 1^ to If in its distance from 



