^ 



I 



THE OPHIURIDiE. 



119 



i 



12* OpMoglypha obtecta n. sp. 



4 



la 



\ 



^ 



Plate II. Figs. 7-9. 



Diameter of disk, 6 mm. ^ width of arm close to disk, 1.8 mm. ; length of 

 armS; c. 25 mm. (the ends broken off). Four shorty close set mouth papillae 

 to each side of mouth angle, the outermost very broad, the innermost 

 pointed, as is that on the apex of jaw. Mouth shield hourglass-shaped, with 

 an obtuse angle within, outer edge rounded ; longer than broad. Side 

 mouth shields long, narrow, equally broad, meeting within. 



Ventral plates separated from the fifth, the four inner ones more or less 

 broadly in contact. First ventral plate with outer edge strongly rounded 

 and with a truncated peak within ; not much smaller than the next ones. 

 They have all the outer edge rounded ; second to fourth (fifth), with inner 

 end truncated : from the fifth they have an angle within. Inner and outer 

 laterals re-enteringly curved, the latter on account of the tentacle pores. 

 The three or four first plates are somewhat hollowed along the median line. 

 Side arm-plates with outer end a little prominent, meeting below from the 

 4th joint, above only from about the 14th. Dorsal plates rectangular, the 

 innermost as broad as long, becoming gradually narrower farther out; 

 from the 13th-14th joint they are triangular, with a very acute angle 

 within, and from here they are separated by the side arm-plates. The 

 sides of these rectangular plates are a little concave. 



Disk scaling rather pecuhar; the primary plates are round and thick, and 

 between them there are small, very indistinct scales. Radial shields con- 

 spicuous, almost egg-shaped, meeting in their middle part, separated within 

 by the disk scales, without by the two first rudimentary dorsal arm-plates. 

 No great marginal plate in the interbrachial spaces. Ventral side of the 

 disk almost wholly covered by the mouth shields, only a few small scales 

 besides that ; the margin of the disk is very high and rather abrupt, with- 

 out any sharp edge between ventral and dorsal sides, covered by small 

 scales. Genital scales rather large, especially their outer end, which 

 passes to the dorsal side of the arm. The papilla) along the genital slits 

 are few and very small, rounded ; as they pass to the dorsal side of the arm 

 they become longer and pointed, making a well developed arm-comb, of 

 which 6-7 papillae are seen from above. The edge of the genital plate 

 is here delicately furrowed. No secondary arm-comb. 



% 



