40 
THE VOYAGE OF H.M.S. CHALLENGER. 
The reddish deposits (PL II. fig. 6, h) resemble those in Trochostoma violaceum, though 
generally smaller. The fusiform rods (PI. II. fig. 6, d) also bear a strong resemblance to 
those in the species just mentioned. Having a length of as much as 1 ‘4 mm. or more, 
they are very closely crowded side by side in the anterior and posterior portions of the 
body, while at the middle of the body they are more separated from one another as well 
as of a more irregular form. They are quite smooth, and their enlarged centre is pierced 
by three to nine holes of varying size. Sometimes a third arm runs out from the centre ; 
as a rule, these fusiform or three-armed deposits appear to be more irregular than is the 
case in Trochostoma violaceum. 
The smaller, perforated plates (PI. II. fig. 6, e) are scattered among the former and 
present a very irregular shape. Generally they are of a more or less rounded or oblong 
form, with two to four or more short arms or sometimes without such. Eeaching a length 
or diameter of about 0'4 mm., they always carry a long simple central process, the top of 
which carries some spines. Here and there some very minute deposits are to be found 
provided with a comparatively long central process which carries at its top several hooks 
(PI. II. fig. 6,fg.). The spoon-like deposits (PI. II. fig. 6, a) and their mutual position 
will be best understood by a glance at the figures. They are generally aggregated, five 
to seven in each group, so as to present the appearance of stars. Each such aggregation 
is provided with a very long, straight, outwardly directed rod, the base of which 
(PI. II. fig. 6, h) is round, discoidal, perforated and slightly convex upwards. These 
central rods are mostly broken off, but when uninjured their tops have the form of 
anchors with the flukes provided with three or more distinct serrations, thus resembling 
the anchors found by Danielssen and Koren in Ankyroderma jeffveysii and Ankyroderma 
affine (PI. II. fig. 6, c). 
Ankyroderma simile, n. sp. (PI. II. fig. 5 ; and PI. XL fig. 2). 
Body fusiform, anteriorly truncated, posteriorly decreasing into a narrow caudal 
portion. Tentacles fifteen, comparatively large, and provided with a pair of minute 
processes near the rounded ends. Anus surrounded by five calcareous teeth and fifteen 
minute cylindrical papillae, disposed in groups of one tooth and three papillae in each. 
Calcareous deposits very scattered — small rounded reddish or light brownish bodies 
mostly aggregated into smaller masses ; small and thinly scattered rings supporting a 
crown of three to four straight outwardly directed rods ; and very thinly dispersed star- 
like deposits, consisting of about five spoon- like rods, with the enlarged perforated 
ends overlapping one another, and a long straight outwardly directed central rod, the 
top of which is provided with two curved arms thus bearing some resemblance to the 
anchors in Synapta. Colour in alcohol dirty grey and yellowish-brown. Length 100 to 
110 mm. 
