FISHES RAJAE. 



369 



fin than the nostrils. The pectorals are very large, sub-triangular, posteriorly expanded, and 

 concave upon the latter margin ; their extremities extending somewhat beyond the insertion of 

 the spine at the first dorsal fin, when stretched alongside the body. 



The scales are very small, closely approximated, and somewhat rougher on the upper surface 

 of the body than on the lower surface, owing to a proportional development of their respective 

 keels. 



The color above is of a dark greyish tint, with a few small whitish-yellow spots, irregularly 

 scattered ; under the head and along the belly, dull yellowish ; under the caudal region, of a 

 greenish grey hue. 



In the embryos the ground color is more of a bluish tint, and the lighter spots just alluded 

 to are much more conspicuous than in the adult, constituting longitudinal series, in which the 

 spots sometimes unite to form a continuous band, increasing in width towards the caudal region, 

 where the lowermost merges into the uniform tint of the abdomen. 



List of specimens. 



SUB-ORDER II. 



RAJAE. 



The rays or skates may be distinguished from the sharks by a depressed, broad, elongated, or 

 short body, terminated by a slender, sometimes flagelliform tail ; a complete thoracic arch 

 extending to the dorsal region ; the pectoral fins confounded, or else continuous with the 

 cephalic region ; the eyelids being either absent or immovable ; the branchial fissures, five 

 on either side, situated on the ventral surface beneath the pectoral fins, and by the anterior 

 portion of the vertebral column, which forms a continuous cartilaginous mass, without any 

 vertebral division. 



SYN. Rajidae, BONAP. Sagg. Distr. metod. Anim. Vert. 1831, 122; Syst. Vertebr. 1837, 44 ; &, Selach. Tabul. analyt. 



1838, 3. -DE KAY, NewY. Faun. IV, 1842, 366. MULL, in Wiegm. Archiv fur Naturg. 1845, I, 137. 



STOKER, Synops. 1846. 



Rajae, MULL. Vergl. Anat. Myxin. I, 1836. MULL. HENLE, Syst. Beschr. Plagiost. 1841, 103. 

 Raladae, BD. Iconogr. Encycl. II, 1850, 242. 

 Hypotremes, DUM. Ichthyol. analyt. 1856, 137. 



We have, so far, but few observations to put on record regarding the rays of the western 

 coast of North America. If we are at all justified in expecting to find there the same approximate 

 number of species as we are acquainted with along the Atlantic coast, many more may be 

 pronounced undiscovered as yet. 

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