NO. 3663 CIRRIPEDIA—ROSS 13 
| 
consequently, it is regarded herein as a full species and cited 
accordingly. 
Subgenus Tetraclitella Hiro, 1939 
Tetraclita (Tetraclitella) divisa Nilsson-Canteil 
Tetraclita divisa Nilsson-Cantell, 1921, pp. 93, 362, text-figs. 8, 83, pl. 3 (fig. 11).— 
| Visscher, 1927, p. 201, fig. 68.—Hiro, 1939, p. 275, fig. 15.—Zevina and 
Tarasov, 1963, p. 96, fig. 13.—Stubbings, 1967, p. 291, fig. 21. 
Tetraclita (Tetraclitella) divisa subquadrata Ross, 1961, p. 210, pl. 4, fig. 1-5. 
Tetraclita costata.—Pilsbry, 1928, p. 316. 
MarTeriAu.—Western side of Panto Hole Bay, east of town of 
Marigot, approximately 15°32’21” N, 61°17/31” W; intertidal, on 
Tetraclita stalactifera; May 1-10, 1966; 2 specimens. 
Draenosis.—Shell covered by persistent, hirsute, chitinous mem- 
brane; parietes furnished with prominent, radial ribs. Radii with 
horizontal summits parallel to base; external surface covered with 
horizontal ridges scored at regular, close-spaced intervals. Scutum 
broader than high; adductor ridge of variable degrees of prominence, 
and apically fused with articular ridge to effectively form roof. 
Tergum only slightly higher than wide; both terga form about one- 
third of bulk of operculum; spur extremely broad and separated 
from basiscutal angle by less than one-half its own width. Few low 
denticles on both sides of shallow, saddle-shaped groove in labrum. 
Cutting edge of mandible armed with 5 teeth including strongly 
serrate inferior angle, not furnished with comb. 
SUPPLEMENTARY DESCRIPTION.—The small size, peltate form; regu- 
larity of shell ornamentation and outline, and the pale purple or 
whitish-purple shell of this species should serve as readily recognizable 
features for field identification. 
Measurements (in mm) of the two specimens in the present col- 
lections are as follows: 
shell opercular plates 
carino-rostral 
specimen diameter lateral diameter height scutum height tergum height 
1 feel Ileal 3.9 4.2 4.0 
2 8.2 7.6 2.6 3.7 3.0 
In view of the excellent available descriptions of this species by 
Nilsson-Cantell (1921), Hiro (1939), Zevina and Tarasov (1963), 
and Stubbings (1967), nothing more need be added at this time; 
however, the specimens were dissected, and cirral counts are given 
below for each of them: 
