A MONOGRAPH OF THE EXISTING CRINOIDS 147 



Of the specimens from Blake station 269, one with 10 arms and one with 13 have 

 the data character developed to an extreme degree; another with 18 arms is not so 

 extreme. 



A specimen from Blake station 232 has 20 slender arms which are only very 

 slightly broadened in the middle. 



There are 2 rows of cirri on the centrodorsal. The cirri have 3 short basal seg- 

 ments, and sometimes the fourth also is not elongated ; the fifth and sixth segments 

 are always long, and those following short. Dorsal spines are developed from the 

 sixth or seventh segment onward. There are 20 + segments. 



The radials are only visible in the interradial angles. The IBr, are in the closest 

 lateral contact. On each ray the 2 IIBr series are interiorly in the closest contact 

 and are sharply flattened against each other. The arm bases are broad and lie close 

 together. Slight synarthrial tubercles are developed in the division series. There is 

 a small depression on the dorsal side of the axillaries. 



The high eversion of the brachials begins with the third, sometimes even with the 

 second ; it increases rapidly in size and extends for varying distances along the arms, 

 but beyond the twenty-fourth brachial the profile of the arm becomes smooth again. 

 On one arm the seventh-seventeenth brachials have extraordinarily developed ever- 

 sions, while from the eighteenth on the brachials are almost smooth. 



Syzygies occur between brachials 1 + 2 and 3 + 4, the next from between brachials 

 21 + 22 to between brachials 36 + 37, and the following after an interval of from 12 to 

 14 muscular articulations; on one arm there is another syzygy 12 muscular articula- 

 tions further on. 



The color is uniform light brown, some of the arms with a dark longitudinal 

 band on the dorsal surface. The dorsal portion of the animal as far as the third 

 brachials is darker. The cirri are light. 



Hartlaub remarks that this specimen and another from Blake station 249 differ 

 from the types of alata especially in the close approximation of the rays, and the 

 apparent tendency of these to come into lateral contact. 



A specimen from Blake station 249 has the centrodorsal with a central concavity. 

 The cirri are arranged for the most part in a single marginal row. There are 20 + 

 cirrus segments of which the 3 first, and sometimes also the fourth, are short; the fifth 

 and sixth are always elongated, and those following are short. Dorsal spines are 

 developed from the sixth or seventh onward. 



The radials are only visible in the interradial angles of the calyx. The IBr, are 

 in the closest lateral contact. The division series are broad and lie very close together. 

 The IIBr, are interiorly in close contact, though this is not always true of the IIBr 

 axillaries. Slight synarthrial tubercles occur in the division series. 



The general habitus of the animal is robust. There are 20 arms which are narrow 

 at the base but gradually broaden, becoming in the middle unusually broad. 



Syzygies occur between brachials 1+2 and usually 3 + 4, sometimes 4 + 5 or 

 5 + 6; the next is from between brachials 18+19 to between brachials 23 + 24, and 

 those following occur at intervals of from 7 to 9, distally 5, muscular articulations. 



The 2 first syzygial pairs are about as long as broad. The 2 brachials following 

 are short and oblong, and those succeeding are short triangular; at about the thirtieth 

 the length slowly decreases and the brachials become irregularly wedge-shaped. 



