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THE OPIIIURIDiE. 



115 



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ft 



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edges double curved^ the former convex, the latter concave, lateral sides 

 straight ; outer edge a Httle wider than the inner edge. The first three or 

 four dorsal plates more or less rudimentary, with a naked space at the sides. 

 No distinct incisure in the disk at the arm-basis. Arms very wide and flat, 

 slightly rounded below, with a keel above. 



Dorsal side of the disk rather curious looking : there is a little naked 

 central space, which in each radius and interradius is prolonged towards the 

 margin, thus taking the form of a star. A broad band along the margin is 

 covered with small, but rather distinct, overlapping scales, which also cover 

 the inward prolongations between the rays of the naked central space. 

 Eadial shields very small, triangular, with outer 

 separated. Under side of the disk also covered with small, distinct, over- 



edge curved, widely 



lapping scales. Genital scales distinct only in their outer part, where thej^ 

 pass to the dorsal side of the arm; here they appear as a rounded plate, 

 bearing an arm-comb, which consists of 6-8 very long and thin pointed 

 papillo3. Genital papilla? also long and needle-like. 



Three well developed pointed arm-spines, the lowermost one about as long 

 as an arm-joint, the two upper ones about as long as two joints. The tentacle 

 pores seem to be distinct in the whole length of the arm ; first pair opens into 

 the mouth slit. Only on the first joints the pores are in contact with the outer 

 corners of the ventral plate ; farther out they are distinctly separated from it. 

 (In G. mollis the pores lie along the sides of the ventral plates.) Tentacle 

 scales rather numerous, long and flat; first pair of pores has 4-5 on each 

 side; those on the inner side already have disappeared from the c. 6th joint; 

 those on the outer side diminish in number: from the c. 9th joint three, 

 from the c. 12th two, and from the c. 20th only one scale, which seems to 

 continue to the end of the arm. 



ray, with a distinct bluish tint, especially on the 

 naked parts of the disk. 



Five large specimens from Station 3431, 995 f . ; from Station 3429, 

 919 f . ; there are some broken arms of this species. 



The two species of Gpnnopldura here described are not very closely 

 related, and might even be regarded as types of two subgenera; however, 

 before more species of this genus are known, such subdivision is not needed. 

 OjMogli/jjha inermis Lym. possibly is nearly related to G. cceridcscens. Of 

 this species Lyman- says (Challenger, p. 12) that it ^^ stands on the limit of 

 Oplimjhjijhar If it should turn out to belong to the genus Gmnnophmra 



Color in 



alcohol : g 



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