106 PROF. A. DENDY AND ME. E. HINDLB : ADDITIONS TO 



genital duct {g-d.) runs forward along the dorsal mesentery and then on the 

 introvert to open by a small aperture situated between the two large tentacles 

 of the mid-dorsal inter-radius. 



This species somewhat resembles Phyllopliorus Driimmondii (Thompson), in 

 which also spicules are typically absent from the body-wall. They differ from 

 one another chiefly in the size of the calcareous ring, which is little more than 

 one-tenth the length of the body in P. .Drummondii, whereas it is one-third 

 the length of the body (in its retracted state) in P. dearmatus. In our species 

 again there is only one Polian vesicle, whereas in P. Dt'ummondii there are two 

 or three. Finally, the geographical distribution is quite different, P. Drum- 

 mondii having been recorded only from the Northern Hemisphere. Without 

 hesitation, therefore, we consider our specimens to represent a distinct species^ 

 and propose the name dearmatus in view of the fact that it has lost the 

 spicules of the body- wall. 



PsEiJDOcucuMis BicoLUMNATUs, sp. n. (Plate 11. figs. Q, & a ; Plate 12. 

 figs. 13, 14.) 



A single example of this species was obtained by Mr. A. Hamilton off 

 Dunedin. 



The animal is cucumiform, tapering slightly at both ends, and possesses a 

 short and inconspicuous conical tail (PI. 11. fig. 6). The length of the body 

 is 3'5 cms. and the greatest transverse diameter is 1*25 cms. The tentacles 

 are completely retracted within the pharynx. 



The tube-feet are entirely restricted to the five radii, thereby giving the 

 animal a very well-marked external radial symmetry. For the greater part 

 of its length they form two double rows along each radius, but towards the 

 anterior and posterior ends they are arranged in two single rows. The tube- 

 feet are more numerous on the ventral than on the dorsal surface, and about 

 the middle of the body may even form six irregular rows on each ventral radius. 



The inter-ambulacra are quite naked. 



There are apparently nineteen tentacles, arranged in two circles round the 

 mouth, at the anterior extremity of the body. The outer circle is formed by 

 five pairs of large and richly branched arboriform tentacles, each about 

 0"7 cm. long. The inner circle is apparently formed by nine smaller tentacles, 

 four pairs and an odd one alternating with the five pairs of large tentacles 

 external to them. Probably there are normally five pairs of sm.aller tentacles 

 in this species, as, in our specimen, there appears to be the remnant of another 

 by the side of the odd tentacle, and it seems likely that the tentacle has been 

 lost by accident ; so that the total number would probably be twenty. The 

 small tentacles are short and thickly branched, and about 1 mm. in length. 

 Surrounding the circle of tentacles is a complete ring of small digitiform 

 papillae, each about 1 mm. long, forming a very definite circle. 



