4 KE. W. MacBRIDE. 
second point, the occurrence of “ Gitterplatten ” (lattice-plates) as calcareous bodies is of 
common occurrence in the genus Cucumaria. Now, in the number of tentacles, the 
presence of an introvert, and the shape of the calcareous bodies our specimens resemble 
Cucumaria. In the presence of tube-feet on only three radii, they resemble Psolus 
[and Colochirus, F.J.B.], but in Psolus the body is flattened on one side so as to 
form a creeping sole, whereas in our specimens the body is almost cylindrical, as in 
Cucumaria. But to me the strongest evidence of their relationship to this genus 
is seen in their resemblance to the young Cucumaria—probably C. lactea, which | 
obtained at Plymouth in 1905, one of which is shown in fig. 4. Here too we find 
that the tube-feet are not developed on all the interradii, but are confined to two. 
Prof. Ludwig (4) notes that in the development of C. planci a pair of tube-feet 
are formed at the termination of the median ventral water-vascular canal and remain 
for a considerable time the only tube-feet. These two terminal tube-feet are clearly 
marked in transverse sections of our specimens (Pl. IL, fig. 8c). 
Our specimens, then, belong to the genus Cucwmaria, but they show as yet no 
obvious traces of the characteristic pulmonary trees. They are, however, quite adult 
in their mode of obtaining food, for the stomach is filled with the half-digested remains 
of Aleve. 
It would seem that a similar stage occurs in the development of Stichopus 
japonicus. Professor Mitsukuri (8) has found that the just metamorphosed form has 
“a coat of armour,” consisting of “disked tables with tall spires united by several 
cross-beams, which cover the body thickly, their bases even overlapping one another 
when shehtly contracted. The ventral pedicels were in three rows.” 
Pl. L., fig. 5 shows a longitudinal sagittal section through a specimen in which the 
course of the alimentary canal is quite straight, and in which both mouth and anus are 
involved. No endeavour has been made to represent the histology, but the general 
relationships of the organs are clearly shown. The mouth leads into an cesophagus 
surrounded by a very thick layer of muscles. On this follows a long conical stomach 
filled as noted above with Alov. The stomach leads through a short intestine into 
the thin-walled cloaca which is attached to the sides of the body-wall by muscular 
strands traversing the ccelom. I was at first inclined to think that our specimens 
might be older stages in the development of Cucumaria crocea, the embryos of which 
have been described by Mx. Simpson and myself (6). But this cannot be the case, for 
in these embryos the alimentary canal is already folded. The stone-canal ends blindly 
in a thin-walled sac (av., fig. 5) embedded in the body-wall; there is no pore-canal 
leading from this sac towards the exterior such as was described by Mr. Simpson 
and myself in the case of the embryos of Cucwmaria crocea in an earlier report, 
nor is there as yet any communication with the body-cavity such as exists in the 
adult Holothurians. This sac corresponds to the axial sinus of other Echinoderms. 
The genital base (Pl. 1, g. 0., fig. 5), from which spring the rudimentary 
genital organs, may be seen close to the stone-canal, but there is as yet no genital 
