284 NEW STARFISHES AND OPHIVRANS—VERRILL. vouxvii. 



the inner end usually bears also a pair of very slender, acute spines 

 directed orally, one on each plate, but sometimes some of the jaws have 

 three or four inner spines, and sometimes but one, in the same specimen; 

 each half of the jaws also bears a inuch larger and longer spine on the 

 actmal surface at the extreme outer end, corresponding in size and 

 position with the adjacent adambulacral spines. All the mouth-spines 

 are covered with membranous sheaths, often sacculated, and bearing 

 large numbers of minute pedicellarite, among which are some of much 

 larger size with strongly curved jaws. 



The slightly tumid genital region of the rays extends about one- 

 fourth the total length ; this portion is evenly rounded on the upj^er 

 surface and densely covered with angular imbricated scales, each of 

 which usually bears a transverse group of small, sharp spinules, simi- 

 lar to those on the disk (the number varies from one or two to six or 

 eight) ; they frequently form comb-like clusters on the sides of the arms, 

 where they are most numerous. In some of the larger specimens some 

 of the large plates on the sides of the arms bear, here and there, a 

 single spine three or four times as large as usual. Beyond the genital 

 region the ray is somewhat triangular, with a strong bilobed dorsal 

 carina due to the ambulacral plates showing through the thin dorsal 

 membrane. The rays taper very gradually to a long attenuated distal 

 portion. The carinated portion of the ray is crossed by broad bands 

 of minute pedicellarite corresponding with each adambulacral plate. 

 The ray terminates with a rather conspicuous plate at least twice as 

 wide as the ray near it ; seen from above it has an obovate form swollen 

 in the middle and bilobed on the proximal end; on the rounded aboral 

 end there are six long, slender spines, of which the two median ones 

 are smallest and the lateral ones as long as, or longer than, the length 

 of the plate; at the extreme outer end of the plate there is a projection 

 beneath which the eye is situated. 



The adambulacral plates are numerous, rather short, and narrow; 

 the furrow side is strongly concave In the middle opposite the suckers, 

 and the distal angle is narrow and prolonged so as to touch or slightly 

 overlap the proximal angle of the succeeding plate. The sutures 

 between the plates are rather wide and moderately oblique. Toward 

 the base of the rays, in the larger specimens, each plate usually bears 

 a single, long, transverse spine on its distal angle; these spines, extend- 

 ing more than half across the groove and overlai)ping the spine of the 

 opposite side, serve to separate the pairs of suckers. Along the 

 thickest part of the ray some of these plates have two similar trans- 

 verse sj)ines, one just above the other, but the extra spine seldom 

 occurs on the smaller specimens. On the prominent actinal surface 

 each plate bears a much larger, long, slender, acute, strongly fluted 

 spine; back of this there is another row of similar large spines one- 

 half as numerous, which often appear to stand on tlie outer distal angle 

 of the adambulacral plate, but on certain parts of the ray the small 



