252 BULLETIN OF THE 



Width of arm at disk 16 mm. ; width of first fork at its base 6 mm. ; at 

 the fifth branch 3.3 mm. ; at the fifteenth branch 1.7 mm. ; at the twentieth 

 branch 1.2 mm. General surface of arm smooth, without spines or grains; 

 a lens shows a fine network of cross-lines which make an ill-defined mosaic. 

 Each joint is marked by a minute ridge placed in a sunken line and running 

 over the top of the arm and ending on either side near the tentacle-pore. 

 These ridges (about 2 mm. apart at base of arm) consist of minute papilla? 

 not more than .3 mm. long, sometimes in a single row, but more often in zig- 

 zag or alternating order, so as to make an almost double row. Each papilla 

 consists of a hook covered with a thick sheath of skin, and either mounted on 

 a very small base, or else sitting directly on the arm. Approaching the tip 

 of arm, the hook-rows become more and more annular, till, on the fine twigs, 

 they completely encircle the arm in a single row. In this way one or two 

 hooks nearest the tentacle-pores often are prominent, so as to appear like 

 tentacle-scales, though really there are none. Disk essentially naked, 

 although, when partially dry, scattered microscopic grains are seen. Radial 

 ribs regular, rather high, with the outer end cleanly cut off; they are covered 

 with a smooth, close, fine granulation ; about eight grains in the length of a 

 mm. Mouth-papilla?, teeth, and tooth-papilla? all flat, spiniform, and similar; 

 about twenty-one in all ; those that represent teeth are about three, and are 

 longer than the others. One large madreporic body at the inner angle of 

 interbrachial space, close against the line of separation between upper and 

 lower surfaces. Genital slits 5 mm. long, and lying under outer ends of 

 radial ribs. Color, in alcohol, above, yellowish brown ; below and at ends 

 of twigs, much lighter. 



A specimen from Philippines, by Semper. 



Catalogue of the OrmuRiDiE and Astrophytid.e, collected by Prof. C. 

 Semper, and now belonging to the Museum of Comparative Zoology. 



Ophiomastix annulosa Mull. Tr. 



" mixta Ltk. 



" fiaccida sp. nov. 



Ophiocoma scolopendrina Agas. 



" erinaceus Mull. Tr. 

 " brevipes ? Peters. 

 <« (i 



Ophioplocus imbricatus Lym. 



