150 



LOWER IXVERrr.P.RA TES. 



sj)aces, and thus seem to 

 30 to 35 fathoms. 



In all the tdrctroinf;' 



^sdi* 



art of th 

 well 



It was found off Port Jackso 



feiicra, a 



sitiiati 



•ml ..tl 



the 



Hilcr 

 to tl 



n tin 

 and arc |];irall 

 ucnera thi' s|iinrs ai'i 

 arni-|ilatcs, and stand 

 arm. The sjiines ai' 

 tlian in the tirst u'roi 



rm-s]ane.s are 

 dues of the side ami-plates, 

 ■ .■inn, lint in the j'emaininii' 

 •et .ill tlie sides of the side 

 lit at a laruc .-iiiLile \\ itli the 

 ihii^ niiieh more eoiis]iicuoils 

 ami in nian\ eases thev are 



FKi. I.iO. — Ojihioph.lis arnleiifa. 



not only loiii;', hut adorned with rows of small, |ioiiited 

 teeth. In (Jp/iiop/iolis the u]ijier arm-])lates are sur- 

 rounded by a row of sup])lenient;iry pieces, and the 

 lowest spine of the outer arm-joints is a hook. A 

 well-known species is O. iicuhdta, which is found at 

 various de]iths, u]> to 4(itl t'atiioms, on the coast of 

 northeastern America and nortliern Europe, as well 

 it was first described under the 

 leeies, resembles the last genus. 



as in the Arctic seas. It is often called <). hellis^ 

 name before given. Oji/iiaiiis, with twenty-foiii 

 Init the upper arm-plates an' with- 

 out the riuij; of siipjilementary 

 pieces. In both gener.a the arm- 

 spines are stout and smooth. O. 

 saviynyi (0. virescejig) is found 

 along the west coast of North 

 America, from Panama to ('jijie 

 St. Lucas. 



Amphiura is the largest gemis 

 of the order, since it contains eighty- 

 nine known species, all of which 

 have a small and delicate disc, cov- 

 ered with over-lapping scales and 

 showing the radial shields, and long, 

 slender, more or less flattened arms 

 with short s])ines of uniform size. 

 A. maxima, obtained by the Chal- 

 lenger expedition in 9° ."iO' S. hit. 

 and 139° 42' E. long., at a depth 

 of twenty-eight fathoms, measures 

 nearly a foot across from end to 

 end of arms, though the disc only 

 slightly exceeds half an inch in 

 diameter. Op/ii,,ri,l(la differs from 

 Amp/tii(rii jirincipally in the jn-es- 

 ence of small spines upon the scales 

 of the disc. There are, in fact, sev- 

 eral genera that are distinguished 

 from ^Iw^jAiWrt by but slight characters, though the differences between the specie 

 contained in those genera are curiously well marked ami constant. IJniiiplioli 



