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brown, with the border of the disc marked by five lighter spots, 

 which are the pairs of plates at the origin of the rays. It is not 

 difficult to preserve, and I may remark that none of our species 

 appear to possess, in any great degree, the tendency to separa- 

 tion which characterizes those of Europe. 



Ophiolepis rohusta Ayres. This species is quite readily dis- 

 tinguished from any other American species yet known, by its 

 proportions, the length of the rays scarcely exceeding the 

 breadth of the disc. The spines of the rays are few and shorter 

 than half the breadth of the ray to which they are attached. 

 The lateral plates, which bear them, are greatly developed, 

 meeting beneath the ray in such a manner as to separate the 

 inferior plates widely from each other. From the general 

 arrangement of the plates, each ray has the appearance of being 

 loosely imbricated. 



The superior surface of the disc is covered with small, smooth 

 plates. The two plates which, in many species, mark the 

 origin of the arms, are here with difficulty distinguished. A 

 close examination shows a slight difference between them and 

 the adjacent plates of the disc, but this species and the one to be 

 next described give evidence that an importance has been, by 

 some writers, attached to this character to which it is not en- 

 titled. Along that part of the disc bordering the base of each 

 ray is a series of small spines or granules similar to the lateral 

 ray-spines, but smaller. 



The plates forming the angles of the mouth bear from seven 

 to ten teeth. The inter-brachial plates are nearly circular. 



This species I have not seen living. It inhabits Massachu- 

 setts Bay, and all my specimens I have taken from the stomachs 

 of Cod and Haddock caught at the depth of sixteen to twenty 

 fathoms. In the largest the disc is about four tenths of an inch 

 in diameter. 



Ophioderma olivaceum Ayres. The long, slender, lizard- 

 tail rays of this species, its bright olive-green hue, and the 

 activity with which it creeps over the sandy bottom, render it 

 one of the most interesting objects in the localities which it 

 inhabits. Unlike others of the tribe, it appears to shun deep 

 water and is found abundantly near low-water mark, living in 

 many places which are regularly left as pools by the receding 



