28 
THE VOYAGE OF H.M.S, CHALLENGER. 
11. Tentacles twelve, with four digits. 
1. Anchors very asymmetrical, one of the arms being smaller and bent toward 
the shank so as to form a more acute angle with it than does the longer 
arm. 
Synapta peter si, Semper, 1868. 
The short anchor-arm with three to four serrations. The long anchor-arm smooth, 
forming an obtuse rounded angle with the shank. Anchor-handle with irre- 
gular processes. Anchor-plates with uneven margin, smooth holes, and without 
any marked handle. Miliary granules minute, X -shaped. Inner organs 
unknown. 
Hahitat . — Amboina (Semper). 
Synapta asymmetrica, Ludwig, 1875. 
Anchor-arms smooth or serrated. The shorter arm forms a considerably sharper 
angle with the shank than the longer. Anchor-handle without processes, often 
curved. Anchor-plates with smooth or slightly dentate margin, with very 
numerous dentate holes, and without any marked handle. Miliary granules — 
small, regular plates, with four dentate holes. Four Polian vesicles. A single 
madreporic canal. 
Habitat . — Banka at Sunda Islands (Ludwig). 
(Mus. Holm.) One specimen obtained at Banka, agreeing in all respects with the 
description of Ludwig. 
2. Anchors almost symmetrical. 
a. Anchor-plates oval or elongate with a distinct narrow’ handle, 
almost complete margin and comparatively fewer holes. 
Synapta dubia, Semper, 1868. 
Anchor-arms smooth. Anchor-plates more elongate, irregularly perforated, with even 
margin and smooth unequal holes, and with some small holes in the narrow 
handle. Miliary granules x -shaped. Inner organs unknown. 
Hahitat . — Bohol and Cebu (Semper). 
Synapta incerta, Ludwig, 1875. 
Anchor-arms serrated. Anchor-plates like those in the preceding species, but more 
symmetrically formed. Miliary gi’anules — minute rods curved like brackets. 
Tentacles and inner organs unknown. 
