66 THE VOYAGE OF H.M.S. CHALLENGER. 



three along the margin being larger than the others. Genital scales narrow, mth a row 

 of seven or eight pointed papillae on the free edge, while the papillae of the arm comb are 

 longer and more slender. Four minute blunt arm spines on the basal joints. The pores 

 of the mouth tentacles do not open into the mouth-slit : they have three rounded scales 

 on either side ; the next two have two scales on either side, and, beyond, two on the 

 inner and one on the outer side. Colom- in alcohol, grey. 



Station 176.— August 15, 1874; lat. 18° 30' S., long. 173° 52' E. ; 1450 fathoms; 

 red clay. 



OpJiioglypha lapidaria, Lym. (PL VII. figs. 16-18). 



OpMoijli/2:>ha lapidaria, Lym., Bull. Mus. Comp. Zool, voL v., part 7, p. 90, pi. iii. figs. 67-69, 

 1878. 



Eleven short, pointed, close-set arm spines. Mouth shields trefoil. Under arm 

 plates squarish. Aljout eight tentacle scales to each pore within the disk. Disk high. 

 Basal under arm plates about as long as broad. 



(Tjrpe specimen from Station 235.) Diameter of disk 11 mm. Width of arm close to 

 disk 2 '5 mm. Five or six short square mouth papillae on each side, and a cluster of two or 

 tlu-ee larger at apex of jaw. Mouth shields longer than broad ; wider without than wdthin, 

 where they present a rounded angle ; outer corners also rounded ; on the later sides a con- 

 striction which gives them a three-lobed aspect ; length to breadth 2-5 : 2*3. Side mouth 

 shields small, long, very narrow ; outer end slightly broader than the inner, where they 

 meet. First under arm plate triangular, with truncated angle inward and outer edge 

 curved ; the next four are four-sided, with curved outer edge ; beyond the disk they are 

 pentagonal, with an obtuse angle inward, short lateral sides, and a long curved outer 

 side. Side arm plates thick, deeply constricted at their inner end ; not meeting below 

 till some distance beyond the disk, separated above by upper arm plates, which are 

 broader than long, wider without than within, the outer edge being curved. Disk thick, 

 covered with large, closely-soldered plates and scales. Radial shields pear-seed shape, 

 longer than wide, with an angle within and outer edges rounded ; touching without, 

 separated within by a single wedge-like plate ; in the centre above is a close rosette, 

 consisting of a pentagonal primary plate, surrounded by five others, smaller and of an 

 irregular shape ; the remaining interbrachial space on the upper surface is occupied by 

 rows of semicircular plates. Lower interbrachial space, covered Ijy small curved, over- 

 lapping plates. Genital scales very narrow, except without, where they broaden into a 

 wide radial scale, bearing a comb of short spines, which continue below as minute 

 papillae on the margin of the genital opening. Ten or twelve fine, short, blunt arm 



