430 bulletin: museum of comparative zoology. 



larger therefore than the Challenger specimens from near the Fiji 

 Islands. The species has not previously been collected since the 

 Challenger report was issued. 



Station 4732. A thousand miles east of the Paumotu Islands, 

 Eastern Tropical Pacific, 2012 fras. Bott. temp. 34.8°. Glob. oz. 



Trichasteridae . 



Asteroschema monobactrum,^ sp. nov. 

 Plate 1, fig. 1, 2. 



Disk, 8 mm. in diameter; arms 80-90 mm. long; width of arm at 

 base, about 2 mm.; height of arm at base, about 1.8 mm. Disk 

 flattened, slightly higher than arms, concave at center (in dry speci- 

 men), covered by a granular membrane; near center of disk there are 

 about 50 granules to a square millimeter, while near margin there are 

 not more than 30. Radial shields almost completely concealed, but 

 in the dry specimen appear as low, rounded ridges, about 3 or 4 times 

 as long as the wider, outer end. Arms rather squarish (in cross- 

 section) at base and wider than high, but becoming more arched 

 dorsally and apparently higher than wide; they are covered by a 

 granulated skin like that of disk but near tip, the granules are more 

 and more separated until the skin is almost naked and the granules 

 very minute. Genital slits very conspicuous, the two together 

 occupying nearly all the interbrachial space; each is 2 mm. long and 

 .60-. 75 mm. wide; the narrow vertical area or ridge separating them- 

 is sunk conspicuously below the rest of the interbrachial area. Oral 

 shields, adoral plates, and oral plates completely concealed beneath 

 granulated skin of disk. Oral papillae (if they can be called such) 

 not more than two on a side, nearer tip of jaw than base, small, rounded 

 and knob like, irregular in form, size, and position. Tooth papillae 

 none. Teeth 4 or 5, rounded triangular. Under arm-plates (if 

 present) at base of arm, concealed by granulated skin; at middle of 

 arm and beyond where skin is thin and nearly or quite naked, there 

 seem to be no under arm-plates. Tentacle-pores small but distinct; 

 diameter equal to about one eighth of distance between first and 

 second pairs of pores on arm. Buccal pair and first arm-pair with no 



' nbvo'i = single + ^aKrpov = club, in reference to the single tentacle-scale on basal pores 

 of arm. 



