Bd. VI: 8) THE CRINOIDEA. I9 



Station 20 (54''i2'S. 36 50' W. South Georgia. 250 m.) . . . . i small specimen. 

 >' 22 (54 17' ' 36' 28' » 75 ) • ■ . . 2 specimens. 



» 34 (54° II' >' 36' 18' •- >' " 252 — 310 m.) . . I specimen. 



All the specimens are in poor condition. Some of them are banded, white and 

 dark brown, on arms and cirri, and spotted with the same color on the disk. One 

 of the smaller specimens from Station 5 has only 18 arms, another only 19, while a 

 larger specimen from the same locality has 23 arms. 



The arrangement of the ambulacral furrows on the disk is very variable, hardly 

 two specimens being alike. The normal condition, evidently, is that each primär}' 

 ambulacral furrow divides so as to provide four arms: but often one or two of them 

 (mostly the left posterior and the right anterior) divide so as to proceed to 6 arms, 

 while others go only to two arms. The point of bifurcation may be at any distance 

 from the mouth, from close to the edge of the disk to very near the mouth, or the 

 furrow to some of the interpolated armpairs may proceed directly from the circum- 

 oral furrow, so that there is apparently six or more primär}^ ambulacral furrows. — 

 It would be of considerable interest to study the mode of formation of the ambulacra 

 of the interpolated arms; unfortunately the material in hand does not afford the oppor- 

 tunity for that, even the youngest specimen (only 5 mm. diameter of disk) having 

 already the 20 arms fully formed. 



A. H. Cl.-\RK regards Pr. ]'anlL'üjfeiiianus Minckert and /';■. Jonbini Vaney 

 as synonyms only of Pr. kergtielensis. The present material does not warrant 

 forming a definite opinion about the correctness of that view. I cannot, however, 

 omit pointing out that in all the specimens in hand the cover plates of the pinnule- 

 ambulacra are entirely absent. This fact is certainly not in favour of the identity of 

 Pr. Vanhdjfeniauus with Pr. kerguelensis. A. H. Clark (Op. cit. p. 132) maintains 

 that the presence of the cover plates is a sign of immaturity; I am not very con- 

 vinced that it is a universal rule that these plates are more developed in the younger 

 than in the grown specimens of Comatulids. In any case it should be emphasized 

 that also in the smallest specimen in hand the cover plates are absent. 



One of the specimens is infested with My::ostonia cysiicoliim \. Graff, a very 

 large cyst being found at the base of the third right posterior arm, close to the edge 

 of the disk. 



After the full account of this remarkable Myzostoina given by R. V. Stummer- 

 Traunfels ' and Cil. L. BoULENGER ^ there is no reason to enter in a more detailed 



' R. V. Stummer-Traunfels. Myzostomida:. National .\ntarctic Expedition. \\. Zoolog)'. 190S. 

 ' Cn. L. BoULK.NGER. Myzostomidœ. British Antarctic (»Terra Nova«) Expedition. Zoology. II. 

 No. 6. 1916. 



