A MONOGRAPH OF THE EXISTING CRINOIDS 133 



The 10 arms are about 50 mm. long. The first brachials are somewhat incised 

 for the sharp proximal angles of the second (there is considerable variation in this 

 respect), both ossicles rising to their line of junction. The sixth and following brachials 

 are smooth and obliquely triangular, much longer than broad, the later ones becoming 

 obliquely quadrate. 



Syzygies occur between brachials 3+4, again between brachials 17+18, and 

 distally at intervals of 4 or 5 muscular articulations. 



PI is much larger than P 2 with wide and thick lower segments which have somewhat 

 flattened outer sides; the third-fifth segments have their inner edge produced into an 

 expanded process which is slightly folded upward. P a and P a are rather larger than 

 their immediate successors, but those following are quite small and increase very slowly 

 in length. 



The disk is 4 mm. in diameter and is well plated. The brachial ambulacra are 

 slightly plated. The pinnule ambulacra are without very definite side plates. The 

 presence of sacculi is uncertain. 



The color hi alcohol is light brownish white. 



Notes. The preceding description is adapted from Carpenter's original description, 

 with a few additions from the published figure. Carpenter said that this species is 

 unfortunately represented only by two calices and half a dozen arm fragments with 

 their pinnules mostly broken. The IBr[ are much compressed laterally so that they 

 appear as it were at a lower level than the axillaries the lateral angles of which overlap 

 and partly conceal them. The state of preservation of the pinnules hi the two individ- 

 uals is unfortunately such that it is impossible to speak positively respecting the presence 

 or absence of sacculi. But there was no trace of them in any of the few pinnules Car- 

 penter was able to examine. No entire cirri are preserved, and Carpenter wrote that 

 the position to which he assigned this species among those with from 30 to 50 spiny 

 cirrus segments is therefore a somewhat conjectural one. He said that it has so many 

 points of resemblance with spinicirra, breviradia, and lusitanica that he had little doubt 

 respecting the character of its cirri. 



Carpenter said that this species is most nearly related to S. spinicirra from which 

 it differs hi the sharper carination and greater relative length of the axillaries. 



I examined one of Carpenter's specimens during a visit to the British Museum 

 hi 1910. It is a small and delicate species and was well figured by Carpenter. 



Locality. Challenger station 175; near Kandavu, Fiji (lat. 1902' S., long. 17710' 

 E.); 2,468 meters; bottom temprature 2.2 C.; globigerina ooze; August 12, 1874 

 [P. H. Carpenter, 1887, 1888; Hartlaub, 1895; A. H. Clark, 1907, 1909, 1912, 1913, 

 1918] (1, B. M.). 



History. This species was first mentioned as Antedon acutirculia by Dr. P. H. 

 Carpenter in 1887, when he said that sacculi are present between the side plates in this 

 species. The name as it appears here is a nomen nudum. 



In the Challenger report upon the comatulids published hi 1888 Carpenter described 

 and figured Antedon acutiradia on the basis of two calices and half a dozen arm frag- 

 ments from Challenger station 175. In the description he said that the presence of 

 sacculi was uncertain and that there is no trace of them in any of the few pinnules 

 he had been able to examine. Dr. Clemens Hartlaub discussed the systematic and 

 bathymetrical relationships of Antedon acutiradia hi 1895. 



