40 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOOr IV. 



Our knowledge of the Americin species has been in a state of great 

 confusion until very lately, the first careful comiiarison of the species 

 ha^-iug been made by Mr. Garman in 1874. On his excellent paper* the 

 following account is based. {Baia or Baja, the Latin name of fishes of 

 this genus.) 



1. — Atlantic Species. 



* Outline of tlie disk anterior to the spiracles rounded, not forming an angle at the 

 tip of the snout. 

 tRows of teeth about ^§. 



48. R. eriiiacea Mitchill. — Common Skate; Little Skate; Tobacco-box. 



Form rhomboid, with all the angles rounded ; spines largest on the 



anterior exten.sions of the pectorals, where they are close-set, strong, 



laterally compressed and hooked backwards ; smaller ones are scattered 



over the head, above the spkacles, above and in front of the eyes, on 



the back, the median line of which is comparatively smooth, without 



larger median series, except in the young. A triangular j^atch on the 



shoulder- girdle ; inner posterior angles of the pectorals nearly smooth ; 



in the males near the exterior angles of the pectorals are two rows of 



large erectile hooks, pointing backwards. Females with groups of small 



scales on each side of the vent ; teeth small, the middle ones sharp in 



the males ; all blunt in the females ; jaws much curved; each side of tail 



with a dermal fold ; caudal fins rough, not separate to the base. Color 



light brown, with small round spots of dark brown ; females larger than 



the males. L. 1 to 2 feet (Garman.) The smallest and commonest of our 



skates; abundant on our coast, especially northward. 



(Baia erinacm Mitchill, Am. Joum. Sci. Arts, xi, 290, 18-2r»: Raia eglantcria Giinther, 

 Tiii, 462; Garman, 1. c. 176.) 



ft Rows of teeth U (f ^ to \i^). 



49. Tt. ocellata. Mitchm.—OccUated May ; Big Skate. 



General form and appearance of the preceding ; the arrangement of 



spines similar, except that additional rows of spines are present down 



the back and along the sides of the tail; caudal fin not separate, rough 



with small spines ; jaws curved. Color light brown, with rounded dark 



spots ; a translucent space on each side of the snout ; near the posterior 



angle of the pectoral there is usually (but not always) a large white 



ocellus, with a dark spot in the centre and a darker border ; two smaller 



similar spots often ji resent {Garman). Size very much larger than the 



* On the Skates (Rajjc) of the Eastern Coasts of the United States: By S. W. Gat- 

 mau. <Proc. Bost. Soc. Nat. Hist, xvii, Nov. 4, 1874, pp. 170-181. 



