A MONOGRAPH OF THE EXISTING CRINOIDS 



241 



borders turning anteriorly along the sides of the ends of the basal rays. The elements 

 of the IBr series have a high well rounded median carination, and the lateral borders 

 are somewhat everted. There is a faint indication of a broad low carination on the 

 arms. 



One of the specimens from the Danish Expedition to the Kei Islands station 58 

 has 18 arms 90 mm. long; of the eight IIBr series present six are 4(3 + 4) and two are 2; 

 one of the post-radial series bears two arms only. Another has 13 arms 100 mm. long; 

 of the three IIBr series present two are 4(3 + 4) and one is 2. Another has 13 arms 

 80 mm. long, there being three IIBr 4(3+4) series. The other two have 10 arms which 

 in one are 85 mm. kmg. 



One of the specimens from the Danish Expedition to the Kei Islands station 59 

 has 16 arms 100 mm. long; of the six IIBr series present four are 2 and two are 4(3 + 4) ; 

 the ornamentation is well developed. Another specimen has 10 arms 80 mm. long; 

 the carination of the IBr series and first two brachials is very low and in conspicuous; 

 the earlier brachials have strongly produced distal edges, but the brachials are without 

 median tubercles or carination. A third has 10 arms 70 mm. long; the edges of the 

 elements of the IBr series and the proximal edge of the axillary are scalloped or tuber- 

 cular ; the keel on the IBr series and first two brachials is fairly well developed, and the 

 broad median tubercles and later low blunt keels on the brachials, though very obscure, 

 may be made out on most of the arms. A fourth specimen has 10 arms about 70 mm. 

 long; the ornamentation is very slight, the carination on the elements of the IBr series 

 being scarcely indicated, and the median elevation on the brachials being broad and 

 exceedingly faint. A fifth specimen has 10 arms 55 mm. long; the elements of the IBr 

 series and first two brachials are unornamented except for the median keel; the distal 

 edges of the proximal brachials are thickened and moderately produced; the median 

 elevation is very slightly marked. Another specimen has 10 arms 95 mm. long; the 

 ornamentation is typically developed. The three remaining specimens are small with 

 10 arms which in one are only 25 mm. in length. 



A specimen from Siboga station 294 was described under the name of Perissometra 

 gorgonia in the following terms : 



The centrodorsal is small, apparently conical. The cirrus sockets are arranged 

 in 10 closely crowded columns. 



The cirri are XXIV, 19-24 (usually 21), from 25 to 40 (usually between 30 and 35) 

 mm. long. The cirrus segments are very uniform in length, the sixth and seventh 

 and following being slightly longer than broad. The distal ends of the segments are 

 slightly prominent, and the distal ends of those in the outer half are slightly thickened 

 on the dorsal side. 



The ends of the basal rays are visible as very large rhombic or rounded-triangular 

 low tubercles or flat areas in the angles of the calyx. 



The radials are concealed. The IBri are extremely short, in the angles of the 

 calyx running far upward and meeting over the ends of the basal rays; they bear a 

 low broad median tubercle. The IBr 2 (axillaries) are rhombic, about two and one- 

 half times as broad as long. Except in the median line their edges, like those of the 

 IBr,, are slightly everted. They bear a large, low, and broad median tubercle. The 

 IIBr series are all 4(3+4) ; each of the component ossicles carries a low rounded median 

 tubercle and has slightly thickened edges all around. 



