Fishes of the Western Nort/i Atlantic 155 



12 b. 25—42 moderate-sized thorns along midline of back, and tail 

 from nuchal region to first dorsal. 



13a. No large thorns on margins of orbits; about 42 thorns 

 in mid-dorsal row. muhispinis Norman 1937. 



Northwest of Falkland Islands. 

 13 b. One thorn at anterior margin and one at posterior margin 

 of each orbit; not more than about 30 thorns in mid- 

 dorsal row. 



14a. Inner parts of pectorals roughened with small 

 scattered prickles; only one thorn on each scapular 

 region. macloviana'Hovvm.n I93 7" 



Patagonian-Falklands region.'® 

 14b. Inner parts of pectorals mostly smooth; each scap- 

 ular region usually with two thorns. 



magellanica Steindachner 1903. 

 Patagonian-Falklands region, and Straits 

 of Magellan. 



Raja ackleyi Garman i 8 8 i 



Ackley's Skate 



Figure 29 



Study Material. Two specimens, a male 410 mm long, the type (Harv. Mus. Comp. 

 Zool., No. 748) and a female 231 mm long (U. S. Nat. Mus., No. 148290), both taken 

 off Yucatan. 



Distinctive Characters. R. ackleyi appears to be separated from R. texana in that 

 the outer margins of its disc are broadly rounded (rather abrupt in R. texand)\ also, on 

 the average the former has a narrower disc, i.i — 1.2 times as broad as long (1.2— 1.35 

 times for texand)\ and its disc is sprinkled with small light and dark spots with the 

 ocellar spots*' oval (disc plain brownish with round ocellar spots on R. texana).^^ The 

 color pattern in itself is enough to set R. ackleyi (and R. texana") apart from all other 

 Skates of the western North Atlantic, except for specimens of R. ocellata on which 

 there is a single large ocellar spot on each side and on which the other dark markings 

 are not conspicuous. The disc and tail of i?. ocellata are so much thornier and the anterior 

 contour is so much more obtusely rounded than those of R. ackleyi that the two could 

 hardly be confused. R. cyclophora Regan 1903,*' from Brazil, closely parallels R. ackleyi 

 (and R. texana) in the presence of a single conspicuous ocellar spot on the posterior 



66. R. maclo'viana Norman 1937 seems so closely allied to R. magellanica Steindachner 1903 that it may prove to re- 

 present a variety of the latter. 



67. In R. ackleyi the distance from the center of the ocellus to the center of the orbit is about i. 0—1.3 times the distance 

 between the centers of the ocelli; in four specimens of R. texana, this distance was 0.83—1.0 times. 



68. If the two species are finally united, the name ackleyi has priority. 



69. For an excellent photograph of R. cyclophora, see Ribeiro (Arch. Mus. nac. Rio de J., 14, 1907: pi. 16). 



