i3-;4. ELASMOBRANCHIATE FISHES— JORDAN AND FOWLER. 643 



jhielly by the fact that the eggs are hatched within the body. The 

 ypical species are also much more elongated in form. 



'. First dorsal opposite to ventrals; caudal with lower lobe well developed. 

 /(. Snout short and rounded, not much longer than interorbital \vidth...7,'////«(, 33. 

 Ill I. Snout narrow, produced and pointed, its length much greater than interor- 

 bital width RkijnchoJxdm, 34. 



■II. First dorsal much behind ventrals; anterior nasal valves not confluent; disk sub- 

 triangular or rlioml)ic; snout more or less produced; skin covered with fine 

 shagreen, usually with somewhat larger s]iines on the ba(;k of tail. 



RIi'iikiIkiIiix^ .'J5. 



88. RHINA Bloch and Schneider. 



Rhina Bloch and Schneider, Syst. Ichth., 1801, p. 352 {ancydoslomux; not of 



Aristotle and Klein, who, before Linnajus, used the name for Squutina). 

 Rhamphobatis Gill, Am. Lye. Nat. Hist. N. Y., 1861, p. 408 {am-tidostonmn) . 



Bod}' depressed, the snout very broad and obtuse, its length not 

 nuch greater than interorbital width, its anterior outline semicircular; 

 jack with large tubercles. Pectoral fins with the anterior margin free, 

 lot extending to the head. Gill-openings narrow, inferior, below the 

 lase of the pectoral. Spiracles wide behind the eye. No nictitating 

 Tieml)rane. Nostrils inferior; oblique, wide slits. Teeth, obtuse, 

 rraiuilar, the dental surfaces of the jaws undulate. First dorsal oppo- 

 ite ventrals; lower caudal lobe well developed. 



(pivy, a shark.) 



35. RHINA ANCYLOSTOMA Bloch and Schneider. 



Rhina anci/Io.stoinu.'< Bloch and Schneidek, Syst. Ichth., 1801, p. 352, pi. lxxii; 

 Coromandel. — Richardson, Ichth. Chin., 1846, p. 195; Canton, and of numer- 

 ous authors. 



RhampJiohatlfi ancuclodomuii Gill, Am. L5'c. Nat. Hist., N. Y., 1861, \i. 408. — 

 DuMERiL, Elasmobranches, 1870, p. 482 (after Bleeker). 



Rhyncobatu.'^ ancijcliMomuii Gf'XTHER, Cat. Fish, VIII, 1870, p. 440; ]\Iadras, China, 

 Seychelles, Pinang. — Day, Fishes of British India, I, 1889, \). 41. 



' Snout very broad, obtuse, with semicircular outline; large, com- 

 pressed tubercles form longitudinal ridges, one on each side of upper 

 part of head, one on median line of trunli; an incomplete series of 

 smaller tubercles round front margin of eye and below spiracle; two 

 short series of small tubercles on each side of trunk may be regarded 

 as continuations of those on head; teeth 77-75, twentj-two vertical 

 rows in center of upper and twenty-seven in center of lower jaw, sur- 

 face deeply undulated, with one large median and a smaller lateral 

 slevation on the lower jaw, and with corresponding emarginations in 

 upper; the teeth are largest on sununit of each elevation, and all are 

 obtusely rounded with several longitudinal ridges across each. Color 

 iull brown, lighter beneath; bod}^ and sometimes fins, covered with 

 whitish s])ots; occasionallv some toi'tuous l)lack liiu>s. ((xunther. 

 Day.) 



