12 
THE VOYAGE OF H.M.S. CHALLENGER. 
be slightly larger and more numerous, and they partly resemble those figured by 
V. Marenzeller, but mostly have a more complicated form (PI. I. fig. 8, b). At first 
sight it may appear as if the difference presented by the miliary granules were of such 
importance as to justify a new species, but at the same time i have seen a great number 
of transitional forms, which evidently prove that the simple x -shaped granules can pass 
over into the more complicated ones. 
The individual in question has twelve tentacles, each with four slender digitations. 
The integument is of a whitish colour, inclining to yellowish, and is covered with 
numerous minute papillae. The madreporic canal, is single and dorsal as to its position. 
No cartilaginous ring behind the calcareous ring. Five ventral Polian vesicles about 
15 mm. long are present. The form of the calcareous ring is best seen by reference to 
the plates. 
There is no doubt that Synapta distincta, v. Marenzeller, is very nearly related to 
several previously known species, viz., Synapta pseudo-digitata, Semper, Synapta 
innominata, Ludwig, Synapta molesta, Semper, and Synapta benedeni, Ludwig. All 
the forms here enumerated seem to be very closely allied to one another. When 
comparing their calcareous deposits, &c., one cannot but think that their distinguishing 
characteristics are mostly very unimportant. Moreover, our present knowledge is too 
unsatisfactory to decide to what degree the deposits of the same species are capable of 
varying in form as well as in size. 
Synapta verrilli, n. sp. (PI. I. fig. l). 
Tentacles twelve, each with four slender digitations. Two larger ventral Polian 
vesicles, about 5 mm. long, and between these two smaller ones. Madreporic canal single. 
No cartilaginous ring. The calcareous ring (PI. I. fig. 1, c) almost like that in Synapta 
similis, Semper, or Synapta molesta, Semper. The anchors (PI. I. fig. 1, a) often 
more or less distinctly asymmetrical, and their flukes commonly provided with about five 
serrations ; the posterior margin of the handle rough from minute serrations. Length of 
the anchors about 0’3 mm. The irregularly rounded plates (PI. I. fig. 1, b) with the 
margin rather uneven and never completed ; their holes are large, comparatively few in 
number, and provided with minute spines round the margin. The holes are smaller and 
more numerous in the articular end of the plates. Length of the plates about 0'27 mm., 
and their greatest breadth about 0'25 mm. The miliary granules (PI. I. fig. I, d) only 
in the form of oval or oblong bodies. Colour in alcohol, yellowish-white. Length of the 
largest individual about 23 mm. 
Habitat. — Station 186, September 8, 1874 ; lat. 10° 30' S., long. 142° 18' E.; depth, 
8 fathoms ; coral mud ; two specimens. 
This species seems to bear the greatest resemblance to Synapta innominata, Ludwig, 
