50 
THE VOYAGE OE H.M.S. CHALLENGER. 
Haplodactyla molpadioides, Semper, 1868. 
Body-wall thick, not transparent. Deposits — numerous small, irregular button-like 
bodies ; and roundish thick bodies strongly furrowed round the periphery and 
with some minute central holes. Five small branched papillae round the anus. 
Habitat. — Bohol and Zebu (the main form), Bohol (var. pdlucida), China (var. sinensis), 
and Singapore (var. jagorii) (Semper). 
As is seen above, the following varieties are referred by Semper to this species : — var. 
•pellucida and jagorii, both devoid of deposits in the perisoma, and var. sinensis. 
All these varieties, however, are not well known. 
Haplodactyla australis, Semper, 1868. Haplodactyla holothurioides, Selenka, 1868. 
Body-wall not transjrarent. Deposits — small flat elongated bodies or grains, with 
the ends slightly enlarged. Anal papillae absent (?). 
Habitat. — Waigou (Selenka), Timor and Padang (Ludwig). 
Haplodactyla hyaloeides, Sluiter, 1880. 
Body-wall thin transparent. Deposits only present in the five short anal-papillae and 
their vicinity, where they have the aspect of branched spicules. 
Habitat. — Batavia (Sluiter), Amoy (Ludwig). 
Sluiter speaks of retractors, but these are probably very rudimentary, and, as usual 
in forms with no retractors or only minute ones, uniting only the calcareoirs ring 
with the most anterior portion of the longitudinal muscular bands; Sluiter 
himself could not observe their attachment to the longitudinal muscular bands. 
The following three forms are unsatisfactorily known and need re-examination : — 
Haplodactyla holothurioides (Molpadia), Cuvier, 1817 ; Semper, 1868. 
Deposits absent in the body-wall. 
Habitat. — Atlantic Ocean (Semper). 
Haplodactyla mediterranea, Grube, 1840; Semper, 1868 ; Ludwig, 1879. 
Habitat. — Mediterranean Sea (Grube). 
Haplodactyla musculus [Molpadia), ^isso, 1826; Semper, 1868; Ludwig, 1879. 
Habitat. — Mediterranean Sea (Pdsso). 
