338 CHarLes LincoLy . EDwARDs, 
chocolate and wood-brown to mulberry or purple, with pedicels some- 
times almost white. 
Stımpson, 1853, records them as black, or dark purple above 
and pale brown or yellowish below, some specimens being of a uni- 
form brieht yellow. 
PourTALEs, 1869, describes an individual as „milk-white with 
yellow spots“. 
Tentacles. — Ten, large and equal. The normal number prevails 
in all but two of the 73 specimens examined. Each of the two variates 
has 9. In one of these, the left tentacle from the mid ventral radial 
canal is missing; in the other specimen the ventral from the left 
dorsal radial canal. Since, in each case, the tentacular canal is well 
developed, it may be assumed that the holothurid originally had 10 
tentacles and that the apparent variation is due to the loss of the 
tentacle by accident. 
Genital papilla. — Sexual differentiation is shown in the 
form of the genital papilla which arises between the two dorsal 
tentacles just posterior to the outer line of their bases. In my 
preliminary report (1909), it is noted that in the female (Pl. 13, 
Fig. 2), the genital papilla is a simple conical structure from 2,5 to 
30 mm. in height and 2 mm. in diameter at the base. In the 
summer of 1909 I examined 12 specimens in the museum of the 
Academy of Science of Stockholm, 10 specimens in the University 
of Upsala, and 13 in the University of Copenhagen. Among these 
I find 4 cases in which the female papilla varies from the above 
simple condition. In two specimens the genital papilla is bifid, in 
tbe third, trifid (Pl. 13, Fig. 3), and in the fourth has the form of 
a flattened dise without subdivisions, but with 5 openings leading 
into the somewhat expanded cavity of the papilla. In one case an 
apparently bifid papilla proved to be simple, with merely a little 
solid elevation of skin simulating a second branch. It is evident 
that these variations are quite different from the condition in the 
male as described below and hence that sex differentiation in the 
form of the genital papilla is established in Cucumaria fron- 
dosa, and as I have shown in another paper, in some of its close 
allies. 
In the male (Pl. 13, Fig. 4), the genital papilla is subdivided 
into from 4 to 30, or more, parts with a general average of 10. 
In side view, the papilla often resembles a cock’s comb, and some- 
times it has right and left halves. In one case the main papilla is 
