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



on their lateral sides a row of minute, sharp papillae ; the rest are long, triangular, with 

 the outer edge curved, and a sharp angle inward, which on the second and third plate 

 is truncated. Disk flat and delicate, covered with very thin, small, closely overlapping 

 scales ; in the centre is a circular primary plate, surrounded by fine irregular scales, then 

 a circle of five primary plates, one in each brachial space, and separating the inner ends 

 of the radial shields, which are long, pear-seed shape, and separated the rest of their 

 length by small scales ; in the interbrachial space there is a row of larger rounded plates, 

 of which the outer one is marginal. Interbrachial spaces below covered with thin over- 

 lapping scales. Genital scales long and very narrow where next the mouth shield, but 

 gradually growing wider above the arm, where they make a long arm comb carrying 

 delicate spine-like papilla? ; on the free edge of the genital scale below there is a row of 

 very short, minute, rounded papillae. Four or five minute, blunt arm spines, equally 

 spaced along the edge of the side arm plate. The pores of the mouth tentacles and the 

 two pairs beyond are long and large, and have from four to six small tentacle scales on 

 each side. Those a little beyond the disk have only one scale on the inner side and none 

 on the outer. Colour in alcohol, white. 



It is very near Ophioglypha lepida except as to arm spines, and basal upper arm plates. 



Station 218.— March 1, 1875 ; lat. 2° 33' S., long. 144° 4' E. ; 1070 fathoms; globi- 

 gerina ooze. 



Ophioglypha imbecillis, Lym. (PI. IV. figs. 11-13). 



Ophioglypha iiribecillis, Lym., Bull. Mus. Comp. ZooL, vol. v. part 7, p. 73, pL iii. figs. 63, 64. 



Three slender, equally spaced arm spines. Mouth shield trefoil, with a long lobe 

 inward. Disk thin, with rather delicate, but rough and angular scales. Arms slender. 



(Type specimen from Station 232.) Diameter of disk 6*5 mm. Length of arm 20 mm. 

 Width of arm near disk 1 mm. Mouth papillae four or five on each side, square, short, and 

 closely set, with a pointed one at apex of jaw. Mouth shields trefoil shaped, with a lobe 

 inward ; length to breadth 1*5 : 1*5. Side mouth shields curved, long, and narrow, of 

 nearly even width, and meeting within. First arm plate triangular, with angle inward, 

 and outer side curved ; second plate, which is largest of all, axe -shaped, with lateral sides 

 re-enteringly curved ; the rest are triangular, with outer side curved, and diminish con- 

 stantly in size. Side arm plates straight and rather delicate, meeting broadly above and 

 below, beyond the second upper arm plate. Upper arm plates triangular, with acute angle 

 inward, and outer edge curved. Upper surface of disk covered with irregular rather thin 

 plates. Eadial shields longer than broad ; outer edges curved, meeting broadly without, 

 diverging inward, where they are separated by a larger and smaller plate. On the inter- 

 brachial margin of the disk is a large oval plate, broader than long, connecting the radial 

 shields ; in the centre a circular primary plate, surrounded by numerous others, irregularly 

 shaped. Genital scales long and broad, bearing three or four papillae near their outer 



