78 Clark — Six New East Indian Crinoids. 



becomes more pointed on the last two or three before tlie penultimate; 

 the opposing spine is small, subterminal, resembling the tubercle on the 

 preceding segment, but arising from a much smaller base. 



The radials and the ends of the basal rays are concealed; the iBr, are 

 very short, broadly V-shaped, sometimes concealed in the median line 

 so that only the lateral portions are visible; the dorsal surface is more or 

 less irregular; the axillaries are short and broad, nearly three times as 

 broad as long, rhombic, the lateral angles truncated so that the lateral 

 sides are nearly or quite as long as those of the iBn. 



The arms are ten or eleven in number, about 180 mm. long; the first 

 two brachials are about equal in size, slightly wedge-shaped (more pro- 

 nouncedly so on the second), about three times as broad as the median 

 length; the synarthrial tubercles are scarcely marked; the brachials have 

 slightly produced distal edges and a more or less swollen dorsal surface. 



Type locality.—" Siboga" Station No. 259. 



Pachylometra Melius sj>. nov. 



This new form is nearest P. septentrionalis of Japan, but it is of more 

 delicate build with much more slender cirri and with the dorsal surface 

 of the division series and arm bases strongly convex and perfectly smooth 

 without any trace of median carination or of tubercles. 



The centrodorsal is of moderate size, flattened hemispherical or thick 

 truncated conical, 6' mm. in diameter at the base, 3 mm. across the flat 

 dorsal pole and 4 mm. high; the cirrus sockets are arranged in ten equally 

 separated columns of two or three each. 



The cirri are about xxv, 23, about 28 mm. long; the first segment is si tort, 

 the following gradually increasing in length to the fifth and sixth which 

 are the longest, between one third and one half again as long as broad; 

 the following segments very slowly decrease in length so that those in the 

 distal third of the cirri are about as long as the distal diameter; in the 

 distal third of the cirri the median portion of the distal dorsal edge of the 

 segments is somewhat swollen, this on the last fiveorsix before the penul- 

 timate becoming a blunt subterminal dorsal tubercle; the opposing spine 

 is prominent, short, sharp, terminal, directed obliquely forward. 



The ends of the basal rays are visible as large rhombic tubercles in the 

 angles of the calyx; the radials are entirely concealed; the iBn are very 

 short, broadly V-shaped with the proximal and distal edges parallel ; the 

 lateral thirds of the proximal and distal edges are slightly produced; the 

 axillaries are very short, nearly or quite three times as broad as long, 

 rhombic in shape with concave sides and truncated lateral angles, the 

 lateral edges being as long as those of the iBn; the lateral edges and all 

 but the median portion of the proximal edge are very slightly produced ; 

 the synarthrial tubercles are low and broad, scarcely evident. 



The basal contour of the animal is broadly rounded, exactly like that 

 of P. septentrionalis. 



The twenty-six arms of the type are 125 mm. long; there are seven 

 ii Br 4 (3 + 4) and three nBr 2 series; the in Br series are 2, internally 



