EEPORT ON THE OPHIUROIDEA. 103 



lower edge of side arm plate, and is a broad rounded scale like those on tlie marginal 

 border. No tentacle scales. Colour in alcohol, pale brown. 



Station 171.— July 15, 1874; lat. 28° 33' S., long. 177° 50' W. ; 600 fathoms 

 (young). Station 174.— August 3, 1874 ; lat. 19° 10' S., long. 178° 10' E. ; 210 to 610 

 fathoms ; globigerina ooze. 



Ophiotrochus. 



Ophiotrochus, Lym., Bull. Mus. Comj). Zool., vol. v., part 7, 1878. 



Disk flat and round, covered with thin, more or less granulated scales, and naked 

 radial shields. Arms slender, tubular, each joint constricted at its base ; side arm plates 

 meeting widely above and below ; upper arm plates rudimentary. Scale of second pair 

 of mouth tentacles lying between side mouth shield and outer mouth papillje. There 

 are teeth and mouth papillge ; no tooth papillae. Smooth arm spines on outer edges of 

 side arm plates. 



Ophiotrochus panniculus, Lym. (PI. IX. figs. 12-14). 



Ophiotrochus panniculus, Lym. Bull. Mus. Comp. Zool., vol. v., part 7, p. 129, pi. vi. figs. 

 158-160, 1878. 



First arm joint, outside of disk, much wider than those beyond, and bearing four 

 slender spines ; the others have only two. A sparse granulation on the lower inter- 

 brachial space. 



(Type specimen from Station 218.) Diameter of disk 6 mm. Length of arm 26 mm. 

 Width of arm without spines "8 mm. Two wide, very short, close-set mouth papillas, 

 occupying the whole of each side of an angle ; and at the apex three more, very small, 

 short, and spiniform. Mouth shields three-sided, with a long angle inward, and outer 

 corners slightly rounded ; length to breadth TS : 1. Side mouth shields much longer 

 than broad, swelled without like a knob, long and very narrow within, where they nearly 

 or quite meet ; they usually bear a few grains. First under arm plate small and rounded, 

 with a slight peak inward ; the rest are somewhat broader than long, pentagonal, with an 

 angle inward, the outer edge rounded, and re-entering curves on the lateral sides. Side 

 arm plates making together a tubular figure, flaring outward, meeting broadly below and 

 above. Upper arm plates very minute, and almost disappearing towards middle of arm, 

 situated at the outer junction of the side arm plates, three-sided, and with a peak within. 

 Disk flat and round, covered with thin dehcate scales ; six rounded primary plates, 

 separated by a line of scales, may be distinguished in the centre ; the rest are more or 

 less angular, and irregularly disposed. Eadial shields broader than long, of irregular 

 shape, with rounded angles, narrowly separated by a single line of scales. Interbrachial 



