444 PROF. L. VON GEAFF ON 



in the Japanese species. The supranodal is not merely grooved to receive the cirrus- 

 bases, as in many species of the genus ; but it actually contributes to form the curved 

 upper edge of the socket itself, which is thus not entirely limited to the nodal joint. 



Traces of this arrangement appear in Metacrinus rotundas (PI. LII. figs. 4, 5), though 

 they are far less marked than in M. Stewarti. 



In consequence of the upward direction of the cirri, and the termination of the 

 cirrus-sockets well above the lower edges of the nodal joints, the infranodals are not 

 grooved at all to receive the cirrus-bases (PL LII. fig. 10) ; so that there are no re- 

 entering angles in their regular pentagonal outline, which is quite different from the 

 circular syzygial surface in Metacrinus rotundus (PL LII. fig. 3), and resembles that of 

 .1/. interruptus. The syzygial surface of the nodal joint, however, is somewhat lobate, 

 as in the ' Vega ' specimen. This lobate shape is partly the result of the increase in the 

 width of the nodal joint from above downwards, and its diminution again below the level 

 of the cirrus-socket by the downward slope of its outer surface, which thus becomes 

 visible in a view of the joint from beneath, as shown in PL LII. fig. 15. This is 

 especially marked in the lower side of the figure, and produces a corresponding incision 

 of the infranodal joint, which must not be mistaken for that produced by the downward 

 extension of the socket to receive the base of a cirrus. This, in fact, really does occur 

 in some abnormal sockets, as shown in the lower part of PL LII. fig. 16. 



When all these peculiarities are considered together, it will lie seen that the stem of 

 Metacrinus Stewarti has a distinct character of its own. What its calyx may have been 

 is as yet unknown. That of M. interruptus, and also that of the ' Vega ' specimen, has 

 six radials, while M. rotundus has five (PL LII. fig. 1) ; and it is therefore uncertain 

 in which group M. Stewarti should be placed, while it might possibly even belong to the 

 group which includes M. superbus (PI. LI. fig. 1), with only four radials. 



A large part of one side of the specimen, including many of the cirri, is w r rapped up 

 in a dense mass of what appears to be the remains of a horny sponge, in which are 

 imbedded Foraminifera, broken fragments of shells, and a quantity of earthy and mineral 

 matter. Some of the cirri afford an attachment to sessile Cirripcdes ( Verruca ?), as 

 shown on the left-hand side of PL LII. fis. 13. 



Description of a new Sj)ecies of Myzostoma. By Prof. L. vox Graff, Ph.D. 



Myzostoma cieripeditjm, sp. nov. (PL LII. fig. 19.) 



A single w r ell-preserved individual was found by Dr. P. H. Carpenter attached to the 

 specimen of Metacrinus rotundus which is described by him in the preceding pages. 



Its external form resembles that of Myzostoma Wyoille-Thomsoni, mihi *, which infests 

 Metacrinus costatus, P. II. C, and M. angulalus, P. If. C, and has beeu described by 

 myself in the ' Challenger' Report. 



* Zoology of the ' Challenger' Expedition, part xxvii. pp, 45-40, pi. vi. figs. 1, 2. 



