OPHITTRA. Ill 



Oral plates short shield-shaped, the hreadth and length ahout 

 equal ; the outer and lateral edges form a regular curve, the inner 

 edges make an obtuse angle. Mouth-papillse four on each side of 

 each mouth-angle ; the outer one is flat and broad, the others are 

 slender, acute ; the median papilla is larger, acute. The inner ten- 

 tacle-pore is small, and usually has a single small scale on each side ; 

 the others have one small scale. The arms are not very long, taper- 

 ing to rather slender tips, with a median ridge. Ventral arm-plates 

 ■widely separated, crescent-shaped, wider than long, those near the 

 base with a proximal angle. Upper arm-plates raised into a distinct 

 median ridge, with a slightly prominent outer angle; those near the 

 base are much shorter than broad ; distally they become much longer 

 than broad. Arm-spines three, rather slender and acute, the upper 

 one is decidedly longer and larger than the next, its length equalling 

 two arm-plates ; the lowest is much the smallest. The genital slits 

 have a row of very minute spinules along the upper half. 



" The colour is variable ; the disk is usually prettily marked by 

 a rosette of brown or dark-grey spots on a paler ground, or the 

 darker tint may take a star-shaped form, with five or ten rays, with 

 the radial shields usually pale ; or there may be a combination of 

 the rosette and star ; rarely the- disk is nearly uniform pale grey, 

 like the upper side of the arms. The larger specimens have the 

 disk 10 mm. in diameter ; length of the arms about 45 mm. 



" This species is rather common in this region in deep water ; we 

 have also frequently dredged it farther north, in the Gulf of Maine; 

 Bay of Fundy ; and off jNova Scotia." 



Specimens stated by Mr. Hoyle to have been dredged in Faeroe 

 Channel, 327-640 fms. 



6. Ophiura affinis. 



Ophiura affinis, Liitk. Dansk. Vid. Selslc. Shrift, v. (1859) p. 45, pi. ii. 



fig. 10; Norm. Ann. fy Mag. xv. (1865) p. 113. 

 Ophioglypha affinis, Lyman, III. Cat. Mus. C. Z. i. (1805) p. 52; 



Ladioig, Mitth. zool. Stat. Neaj). i. (1*79) p. 547 ; Leslie § Herdm. 



Proc.R. Phys. Soc. vi. (1881) p. 87 ; Lyman, Chall. Pep. Oph. 



(1882) p. 77 ; Fjelstrup, Zool. Ban. Piyh. (1890) p. 24, pi. ii. 



fig. 3. 

 Ophiura grubei, Heller, SB. Ah. Wien, xlvi. (1863) p. 431, pi. ii. 



figs. 13-10 ; id. Zooph. u. Ech. Adriat. Meer. (1868) p. 58. 

 Ophiura normani, Hodge, Trans. Tynes. Nat. F. Club, v. (1863) 



p. 296, pi. xvi. 



A very small species, with arms stout at the base. The central 

 and five primary plates of the disk are very distinct and large, and 

 are surrounded by much smaller plates ; aloug the median inter- 

 radial line there are two plates almost as large as the primary, and 

 the remainder are much smaller. The radials are of moderate 

 size, wider without than within ; the arm-comb consists of about 

 ten small spines. Four small teeth ; mouth-shield very large, 

 pointed internally, about twice as long as wide ; bursal slit rather 



