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REPORT ON THE CRINOIDEA. 235 
of the copies of this plate which were sent to,me I found the MS. name Bathycrinus 
campbellianus in Sir Wyville’s handwriting. He had evidently therefore come to regard 
this individual as specifically distinct from those subsequently obtained in the Southern 
Ocean, to which he eventually limited the name Bathycrinus aldrichianus; and the disk 
of this individual (Bathyerinus campbellianus) corresponds in most respects with his 
description quoted above. 
The whole of each interradial area is covered with closely set, calcareous plates, not 
scattered granules ; but 1 cannot make out that they are more abundant in the immediate 
neighbourhood of the mouth than elsewhere. The covering plates of the ambulacra are 
smaller and less regular than in Bathyerinus aldrichianus, and their course can only be 
followed with difficulty. In the solitary young specimen of Bathycrinus gracilis 
(Pl. VIlla. fig. 1) there are neither orals nor anambulacral plates, so that in these 
respects it resembles the southern Bathycrinus aldrichianus rather than the northern 
Bathycrinus carpenters. 
In order that I might be able to compare the anatomy of Bathyerinus with that of 
Rhizocrinus, two of the least perfect examples were cut into thin sections with a Leyser’s 
microtome. Unfortunately, however, the circum-oral portions of the one used for the 
vertical sections were somewhat mutilated, and the remainder was found to be contracted, 
and, as it were, coagulated by the action of the spirit, so that not even its general anatomy 
could be made out, much less any histological detail. The arms, on the other hand, 
yielded more satisfactory results. 
In correspondence with the different size of the basals, the chambered organ (PI. VIIb. 
figs. 1,2, ch) is more flattened than that of Rhizocrinus. It is continued below into thé vas- 
cular axis of the stem, which is thrown into numerous folds as it passes through the closely 
packed discoidal joints at the top of the stem. Asin Rhizocrinus there is only one central 
vessel (PL. VIla. fig. 2; Pl. VIb. fig. 2—v), and not two or more as in some species of 
Pentacrinus and in the Comatulz. The plexiform gland rising from the chambered organ 
expands considerably within the central funnel of the calyx (PI. VIIb. figs. 1, 3-5, «), and 
soon becomes lobulate. It appears to be made up of numerous small cells, which can be 
traced downwards into the flattened epithelial lining of the vessels in its lower part, and in 
the chambers of the chambered organ. But it has nothing like the glandular appearance 
of the corresponding organ in Antedon carinata, the numerous lobules of which consist 
of distinct tubules lined by columnar cells, like those of the urinary tubules. 
On its way up through the disk the plexiform gland becomes narrower again, probably 
on account of its giving off extensions which form the intervisceral vessels, as in other 
Crinoids. It is interradial in position, as usual, and may be followed at the sides of the 
fore-gut both in transverse and in longitudinal section (Pl. VIIb. figs. 6-8, x) to a little 
way below the peristome, where its further course cannot be traced. I have little doubt, 
however, that its connections are essentially the same as in other Crinoids. But owing to 
