74 PROCEEDINGS OF THE ACADEMY OF [Feb., 



» 



Tentacle pores large, without scales. Color in alcohol: disk 

 gray; radial shields and arms straw-yellow. 



Numerous specimens; Aburatsubo Cove: Misaki Marine Bio- 

 logical Station. 



A. cestuarii differs from the foregoing species, A. vadicola, in the 

 shape of the radial shields, in the much shorter arms, in the dorsal 

 arm plates, which are very wide even on the basal joints, and in the 

 fewer, less flattened arm spines. 



A. cestuarii together with A. euopla H. L. Clark are easily obtained 

 by dredging in the muddy bottom of Aburatsubo Cove. They 

 probably live buried in mud, as A. vadicola does in sand, and I 

 believe that, the reduced disk scales and the numerous thorny arm 

 spines are correlated with the mode of life. 



Family 3. OPHIOTRICHID^ Ljungman, 1867. 



(Characters as given in key, p. 66.) 



This family includes Ophiothrix, Ophiopteron, Ophiocampsis, 

 Ophiophthirius, Ophiotrichoides, Ophiomaza, Ophiocnemis, Ophio- 

 thela, Ophiopsammium, Ophiogymna, Lutkenia, Gymnolophus, Ophio- 

 lophus, OphiocEthiops and Ophiosphcera. 



Order iv. CHILOPHIURIDA nov. 

 Radial shield and genital plate articulate with each other by 

 means of two condyles and one pit on either plate. Genital plates 

 and scales bar-like. Peristomal plates small, or sometimes moder- 

 ately large, usually double or triple. Oral frames with or without 

 well-developed lateral wings. Oral papillae very well developed, 

 close set, the outermost one usually pointing inwards and stretching 

 above the next papilla, which is the largest as a rule. 



Key to families of Chilophiurida (/) . 



A — Arm spines short, appressed. 



a — Disk squamated or tessellated, usually free of granules; oral 

 papillse thick; arms stout, stoutest at base, inserted 



laterally to disk Ophiolepidid^. 



aa — Disk closely covered with granules. 



b — Oral papillae thick; arms slender, stoutest usually at a 

 distance from base, inserted ventrally to disk; two 



to four arm spines Ophioleucid.e. 



66 — Oral papillse thin; arms stout, stoutest at base, inserted 

 laterally to disk; numerous arm spines, 



OphiodermatiDuE, pars. 

 AA- — Arm spines long, not appressed. 



c — No vertical clump of dental papillse. 



