* 
20 8 Holothuria floridana 
As a connecting link between the typical pedicel and papilla is an appendage 
not definitely cylindrical, or conical, with suckers either present, rudimentary, or 
absent, having end-plates of Type C. 
I. The Calcareous Ring. 
The typical radiale of the adult (Plate V. Fig. 93), is convex anteriorly and 
slightly concave posteriorly. The anterior half is somewhat expanded, the sides 
sloping in for about one-half the length when they become sti'aight at the junction 
with the inter-radialia. At the middle of the rounded anterior margin of the 
radiale is the notch for the radial nerve. It is 1 mm. wide, cutting into the piece 
for 1 of its length and slightly increasing in breadth toward the bottom. The 
surface rises up from the edge of the notch to a ridge along either side. These 
meet a similar ridge which arises from the posterior margin. In its greatest 
dimensions the radiale is about 6 mm. long, 6 mm. wide, and 2 mm. thick. In the 
young (Fig. 97) the radiale is more delicate, more regular in outline and with the 
median anterior notch V-shaped and decreasing in breadth toward the bottom. 
A variation (Fig. 94), not hitherto described, is often found in which there are 
two additional small notches cutting into the anterior margin, one toward each 
side. Sometimes only 1 of these notches may be found. This variate often occurs 
together with the normal form in the same animal. 
The interradiale of the adult (Fig. 95) has a concave posterior margin and the 
sides run in and forwards from the lines of junction with the radialia to the 
anterior rounded point, thus giving the piece a somewhat triangular form. Two 
ridges follow the sides to unite behind the anterior end. In the young (Fig. 98) 
the interradiale is more delicate and the anterior sides are deeply concave, thus 
leaving the median portion as a bold projection. 
In specimen 5 (which has only 16 tentacles) there is a fusion of the ventral 
and left ventral radialia and the intervening left ventral interradiale (Fig. 90). 
The dotted lines give the outlines of the attachment of the ventral and left ventral 
radial muscles. 
The increase in size of the pieces of the calcareous ring, as age advances, is 
demonstrated by the 3 following specimens ; 94, about midway in the range of the 
young, 42, a small adult and 56, a fairly large adult : — 
Specimen 
EaDIAIjE 
Inteu-radiale 
Number 
Volume 
Length 
Width 
Length 
Width 
Serial 
c.c. 
mm. 
mm. 
mm. 
mm. 
94 
21 
2-8 
2-8 
re 
1-5 
59 
4-0 
3-8 
2-5 
2-5 
56 
485 
5-0 
4-8 
.3-G 
3-6 
