REPORT ON THE OPHIUROIDEA. 83 



somewhat swollen and flaring outward, meeting broadly belnw ; separated above by the 

 upper arm plates, which are somewhat arched, with the inner side narrower than the 

 outer, which is curved. Disk round, smooth, and flat, covered above and below with 

 minute thin scales ; in the centre are several rounded primary plates, and one of nearly 

 equal size in each interbrachial space. Radial shields pear-seed shape, with inner angle 

 blunt, and outer corners rounded ; separated their entire length by fine overlapping 

 scales. Genital scales hidden, except their tips, outside the radial shields, which bear an 

 arm comb of a few minute papillae, as does sometimes the first upper arm plate. Three 

 slender, cylindrical, tapering, pointed arm spines, the upper one being much longer and 

 larger than the two lower ; lengths to that of an arm joint 3*4, 1, '8:1. Tentacle scales 

 minute and rounded ; there are two or three to each of the second mouth tentacles ; 

 usually one on the outside of the basal pores, and one on the inside of the pores farther 

 out on the arm. Colour in alcohol, disk nearly white ; arms above pale grey. It is in 

 general like Ophiocten pallidum, but the flatter and wider arms bear a very long upper 

 arm spine. 



Station 78.— July 10, 1873 ; lat. 37° 24' N., long. 25° 13' W. ; 1000 fathoms ; 

 globigerina ooze. Station 146.— December 29, 1873 ; lat. 46° 46' S., long. 45° 31' E. ; 

 1375 fathoms; globigerina ooze. Station 168.— July 8, 1874; lat. 40° 28' S., long. 

 177° 43' E.; 1100 fathoms ; grey ooze. 



Species of Ophiocten not herein described. 



Ophiocten abyssicolum, Ltk., Addit. ad Hist., part 1, p. 51, 1868. Ludwig, Echin 

 des Mittelmeeres, p. 548. 



Ophiura ahyssicola, Fbs., Linn. Trans., vol, xix. p. 146, pi. xiii. fig. 8, 1843. 

 iEgeanSea; 150-200 fathoms. 



Ophiocten clepressum, hjm., Bull. Mus. Comp. Zool., vol. i., part 10, p. 320, 1869 ; 

 111. Cat. Mus. Comp. Zool., No. vi., pi. ii. fig. 10. 

 Florida ; 315 fathoms. 



Ophiomusium. 



Ophiomusium, Lym., BuU. Mus. Comp. Zool., vol. i., part 10, 1869. 



Teeth ; no tooth papillae ; mouth papillge soldered in a continuous row, so that theii- 

 former outlines are scarcely to be seen. Disk covered by plates and radial shields, aU of 

 which are intimately soldered, forming a surface like porcelain. Upper and under arm 

 plates minute ; side arm plates meeting above and below ; swelled, intimately soldered 



