172 BULLETIN OF THE 



of his original description of P. decorus as a diagnosis of P. mulleri, with a ref- 

 erence under the latter name to the specimen which he had before him when 

 describing P. decorus. He stated that the two outer radials of P. asteria are 

 united by syzygy, and further added that " the arrangement of the joints and the. 

 syzygies in the cup is the same in P. mulleri as in P. asteria, only the syzygy 

 between the second radial and the radial axillary is not so complete." This 

 description obviously refers to a ligamentous articulation as distinguished from 

 a true syzygy on the one hand, and from a muscular joint on the other ; and it 

 is by no means in accordance with Lutken's very positive statements * as to the 

 presence of a syzygy between the two outer radials of P. midleri. Neither does 

 Sir TVyville's description of the nodes as occurring about every twelfth joint 

 agree with Lutken's diagnosis, which only records 4-10 internodal joints in P. 

 mulleri. As a matter of fact there are 11 or 12 internodal joints in P. decorus, 

 and there is no syzygy at all between the two outer radials, but only a ligamen- 

 tous articulation such as occurs in the majority of the Neocrinoidea, and has 

 often been wrongly spoken of as a syzygy, though clearly distinguished from 

 it by Mtiller. 



Had Sir Wyville lived to work out the " Blake " collection more fully than 

 he was able to do before his health gave way, I cannot but think that he would 

 have returned to his original views as to the distinctness of his P. decorus from 

 Oersted's P. mulleri. The two species have really no sort of resemblance to 

 one another, differing in all the characters of the stem, the cirri, the calyx, and 

 the arms. 



Curiously enough, P. decorus appears to be the most common species of the 

 genus in the Caribbean Sea. One of the " Blake" specimens is remarkable for 

 the total absence of cirri along the whole of one face of the stem ; while at one 

 of the nodes two more cirri are missing, so that there are only two present 

 instead of the usual five. 



P. blakei n. sp. 



Stem slender, not reaching 4 mm. in diameter with 5-7 internodal joints. 

 Nodal joints not enlarged. The small circular cirrus-sockets do not nearly 

 reach their upper edges, and extend but slightly downwards on to the hy- 

 p< izygals. 



Slender cirri composed of 25 joints and barely 20 mm. long. 



Lowest limit of the interarticular pores from the sixth to the tenth node. 



The two outer radials united by a ligamentous articulation. Usually only 4 

 arms on each ray. Primary divisions of 1-4 (distichal) joints, of which the 

 first two are united by a ligamentous articulation. If 4 distichalfl an pn n at, 

 the second bean a pinnule and the two outer ones form a Byzygy. The first 

 free brachial bears a pinnule, and the second is usually a sysygial joint, while 

 other syzygies occur on the arms at very irregular intervals. The proximal face 



Loc. at., pp. 201, 202. 



