MONOGRAPH OF THE EXISTING CRINOIDS. 277 



Within the ambulacral lappets is a long, straight or slightly bent rod, some- 

 times two, which is studded with scattered short spinelets in the outer portion and 

 with the outer end expanded, forked, branched, or modified in other ways; from 

 the outer portion of the lappet this passes inwardly and proximally, making an 

 angle of about 45° with the pinnular, along the outer proximal side of the large 

 meshwork first described to the pinnular. 



The genital glands are entirely covered by curious scale-like plates of mod- 

 erate size, subequal, with rounded angles and no reentrant sides, which imbricate 

 outwardly, away from the pinnulars ; these plates have excessively fine jierforations, 

 and usually appear imperforate. 



There are no deposits in the tentacles. 



Pentametrocrinus tuberculatus. — The perisomic deposits resemble those of 

 P. japonicus. 



Over a swollen genital gland the plates in the perisome, which are entirely 

 separated from each other, appear subequal, all subcircular, with a slightlj" thick- 

 ened white spot in the center surrounded by concentric rings of extremely minute 

 perforations. 



Pentametrocrinus varians (fig. 802. p. 378). — At the base of the ambulacral 

 lappet is a large, coarse-meshed plate, with imfinished edges, more or less oval in 

 outline, longer along the longitudinal axis of the pinnule than high. 



Beyond the proximal outer side of this plate, making an angle of 45° with the 

 edge of the pinnulars, is a long, stout, and slightly curved rod, which reaches nearly 

 to the edge of the pinnulars, and of which the outer end, over the distal portion of 

 the large plate, bears on its outer side a few short branches, or two or three meshes. 



The genital glands are completely incased by a pavement of rather small sub- 

 equal polygonal plates of very fine texture. 



There are no deposits in the tentacles. 



Family ATELECRINID^. 



Atelecrinus sulcatus. — Each ambulacral lappet contains in its outer portion a 

 rather conspicuous elongated triangular plate, with the apex at the distal end of 

 the lappet and the longest side parallel to the ambulacral groove; the shortest 

 (proximal) side makes an angle of about 45° with the edge of the pinnulars; these 

 plates are widely separated from each other. 



There are no deposits in the tentacles. 



The occurrence of the several types of adambulacral deposits is shown in the 

 following table : 



o\ No adambulacral structures; the ventrnl perisome is either entirely naked, or contains only 

 minute Irregularly scattered spicules. 



Comatella nigra. Nemaster ruhiginosa. 



ComateUa stelligera. Nemaster discoidea. 



Comatella maculata. Comissia lutkeni. 



Capillaster sentosa. ComisHa littoralis. 



Capillaster muUiradiata. Comatulides auKtralis. 



Capillaster eorcndistnma. Comaster novmguinew. 



