658 MK. A. SMITH WOODWARD ON THE SO-CALLED [NoV. 20, 



below the augle there extends the sensory canal, opening by a 

 series of pores (seen in Brit. Mus. nos. 4294, P. 6456). There 

 are two large postorbital cheek-plates (fig. 3, pt.o.), thinner than the 

 other external bones (except the gular plate), and there are also 

 remains of suborbitals extending to the anterior border of the 

 preoperculum. 



The opercular apparatus is complete and the bones are robust. 

 The operculum (fig. 3, o]).) is trapezoidal in form, about t\^-o-thirds 

 as broad as deep, and marked with coarse branched rugae radiating 

 from the point of suspension. The suhoperculum (fig. 3, SMp.}, 

 likewise ornamented, is almost sickle-shaped and deeply over- 

 lapped by the operculum, and bears a large ascending process at 

 its antero-superior angle. The interoperculum is small, smooth, 

 and much overlapped. The preoperculum (fig. 3, p.op.) is sharply 

 angulated and marked with radiating rugae. There are not less 

 than eighteen brancliiostegal rays (as shown by B.M. no. P. 5680), 

 the uppermost large, broad, and rugose ; and five of these are 

 supported by the epihyal. In advance of the branchiostegal rays, 

 between the rami of the mandible, there is also a conspicuous 

 (jular plate (fig. 1, ^m.), remarkably thin and elongated, but shown 

 both in the specimen figured and in others in the British Museum 

 numbered 4207, 4296, 4299, and 49891. 



The axis of the trunk is only imperfectly known. The vertebral 

 centra are strengthejied by secondary calcifications in the form of 

 small irregular longitudinal ridges ; those of the anterior abdominal 

 region and the hinder caudal region are deeper than long, while 

 the remainder are about as long as deep. Ribs are observable, and 

 there are much thickened neural and haemal arches fused with the 

 centra towards the base of the tail (B.M. no. 4303). Some styli- 

 form bones in the abdominal region of no. 49892 also appear to be 

 intermuscular elements. 



There is nothing worthy of remark in the pectoral arch, of 

 which the long supraclavicle and relatively large and smooth 

 clavicle are shown in a British Museum specimen, no. P. 5680. 

 Th.e pectoral fin-raijs (fig. 1, pet.) are unjoiuted for a considerable 

 distance proximally, and tlie foremost ray (shown in B.M. no. 

 49894) exhibits an oblong expansion at its base of attachment. 

 The rays of the pelvic fins {^g. l,plv.') are not less than 11 in 

 number and are similarly only divided quite at the distal end; 

 their supporting elements ai-e unknown. The dorsal fin, placed in 

 the middle of the back, opposite to the pelvic pair and arising 

 somewhat in advance of the latter, is incompletely known, but 

 consists of robust rays unjointed for a long distance proximally, 

 very closely divided at the distal end ; the supports (shown in 

 B.M. no. 49892) are large and dagger-shaped, having wide 

 "wings." The anxil fin (fig. 1, a.) is small and remote; the 

 caudal fin appears to have been forked (B.M. no. 49891). 



The scales are very deeply overlapping, the covered portion 

 being marked by few radiating grooves terminating at the anterior 

 truncated margin. The posterior border is gently rounded, and 



