REPOET ON THE HOLOTHTJEIOIDEA. 
65 
(PL lY. fig. 8, b). The scales are commonly roimclisli, compact and thick, almost 
resembling a mulberry (PI. lY. fig. 8, c), and do not attain a greater diameter than about 
07 or 0-8 mm. A whole series of transitional forms are to be found between the small 
buttons and these scales, which have evidently been developed from the former. The 
pedicels and papillse are strengthened by plate dike perforated rods (PI. lY. fig. 8, d) and 
terminal plates, the latter being slightly larger in the pedicels. 
Cucumcma mendax, n. sp. (PI. Y. fig. 3 ; PI. XYI. fig. 3). 
Body cylindrical or fusiform. Anus without teeth. Tentacles ten, of almost equal size. 
Pedicels pretty closely disposed, equally distributed all over the body, without traces of 
any arrangement in rows. Surface of the perisoma almost smooth. Deposits numerous, 
crowded, of two kinds — round or oval, rather symmetrical buttons with about four holes 
and ten large knobs, and elongated more or less irregularly formed knobbed plates with 
as many as ten holes, one end being slightly narrower and provided with spines. Pedicels 
supported Ijy terminal jjlates and crowded perforated plates or rods, often with some 
spines on the margin and knobs on the surfaces. Colour in alcohol, yellowish-white. 
Length of the largest specimen, about 70 mm. 
Habitat. — Station 315, January 26, 1876 ; lat. 51° 40' S., long. 57° 50' W. ; depth, 
5 to 12 fathoms ; sand and gravel ; six specimens. 
In the largest sj)ecimen, brought home from the above mentioned Station, the 
arrangement of the pedicels completely resembles that characteristic of the genus Thyone, 
and, at first sight, I even referred it to this genus, but, considering the general 
organisation, it doubtlessly presents the nearest relation to several species of Cucwnaria 
before known. In the five other smaller individuals, on the contrary, an arrangement 
of the pedicels in rows is percej^tible, and especially in the smallest, about 25 mm. long, 
specimens this arrangement becomes most distinct. Thus, the outer aspect of these small 
specimens is very hke that in Semper’s Cucmnaria hoelliheri and Cucumaria dubiosa, 
and Ludwig’s Cucumaria salmini, but they present even a great conformity in their 
internal organisation, as will be seen further on. 
The calcareous ring is of the ordinary shape, without prolongations posteriorly, though 
traces of such are distinguishable in some of the radial pieces. The madreporic canal is 
single, dorsal. Four Polian vesicles are present. The retractors are attached at the 
middle of the body or slightly in front of it. The genital tubes are simjDle, unbranched, 
as much as 40 mm. long. The respiratory-trees in comparison to the genital organs are 
not very richly developed. 
On comparing the descriptions of Semper and Ludwig, it will be found that the 
deposits of Cucumaria mendax almost completely resemble those in the three above- 
mentioned species. The knobbed and spinous plates (PI. Y. fig. 3, a) are situated 
(ZOOL. CHALL. EXP. PART XXXIX. 1885.) Q<1 ^ 
