REPORT ON THE CRINOIDEA. 121 



are longer than wide. The earlier joints overlap slightly, and the later ones more so, 1 

 especially on the dorsal side, so as to produce a blunt spine at the distal edge which is 

 rather sharper on the penultimate. 



First radials entirely concealed in the adult, and sometimes portions of the second 

 also. These are short and band-like, in close lateral contact, with raised edges which 

 are often somewhat crenated, and there is usually a slight tubercle in the middle of the 

 distal border, corresponding to one on the axillary. This is short and pentagonal with a 

 wide, open angle and more or less crenated edges. The dorsal surface is very convex, 

 with the margins more or less flattened, and wall-like sides. First brachials short, nearly 

 oblong and closely united ; the second more wedge-shaped. Both joints rise towards 

 their apposed edges to form a median elevation like that between the second and third 

 radials. The first three brachials wall-sided with flattened margins like the axillaries. 

 The following joints short till about the twelfth, after which they are longer and more 

 triangular, gradually becoming quadrate ; the terminal ones elongated and slightly 

 compressed laterally. Ten arms of about one hundred and twenty joints. In the lower 

 parts of the arms the distal edge of each joint stands up as a sharp crenulated ridge from 

 which the surface slopes backwards. As the joints become longer, further out on the 

 arms, this sudden rise disappears, and they overlap in the ordinary way. 



Syzygia in the third brachials and then very variable in position. The next between 

 the ninth and sixteenth brachials, and others at intervals of one to sixteen (usually 

 three to seven) joints. 



The second brachial has a short pinnule of about twenty -two joints, of which the six 

 lowest are trihedral and rather broad, and much flattened on the outer side, with a 

 marked dorsal keel which is lost in the smaller terminal joints. A similar but rather 

 smaller pinnule on the third brachial. The next pinnule has fewer joints, but the third 

 and fourth are relatively broader, and in the succeeding pinnules very much so, with 

 their outer faces greatly expanded towards the ventral side. This condition is most 

 marked about the twelfth brachial, and then gradually decreases, being traceable to the 

 twenty-fifth or thirtieth. After this it is lost and the pinnnles gradually diminish in 

 stoutness, but do not increase much in length. 



Disk much incised and completely plated, as are also the arms, both along the 

 ambulacra and at their sides. The genital glands protected by stout anambulacral 

 plates. 



The ambulacra of the distal pinnules have well-defined side plates alternating with 

 but often partly concealing the sacculi. These are abundant and very large, especially 

 on the genital pinnules. 



Colour in spirit, — young individuals a yellowish-brown ; the older ones a dark grey- 

 brown. 



1 This is not well shown in the only cirrus remaining on the figured specimen. 

 (ZOOL. CHALL. EXP. — PART LX. — 1887.) OoO 16 



