NO. 3663 CIRRIPEDIA—ROSS 15 
Marerrau.—Scotts Head Bay, at southern end of Soufriere Bay; 
approximately 15°12’40” N, 61°22’40” W; 0.5 meters; May 17-28, 
1966; 5 living and 2 dead specimens on Millepora complanata Lamarck; 
locality no. 2 of Kier (1966). 
Diaenosis.—Basis, radii, and parieties tubiferous. Basal margin 
of scutum sinuous and strongly protuberant medially; growth 
ridges of plate straight and narrow at lateral extremities, but flexed 
basally in medial third. Labrum with 3 teeth on each side of medial 
notch. Mandible with 5 teeth including inferior angle; second tooth 
bifid. Cutting edge of maxilla I straignt. Living strictly on milleporine 
corals. 
SUPPLEMENTARY DESCRIPTION.—This barnacle is readily recognized 
by its habitat, although the shell is commonly overgrown by the 
milleporine. In all of the present specimens the shell is high, conical, 
the parietes slightly to strongly ribbed, and the basis flat. The radii 
are moderately broad with summits parallel to the basis. The sutural 
surface of the radii and opposed sutural surfaces possess septa on 
which both the superior and inferior margins are denticulate. 
Shell and opercular dimensions (in mm) of four dissected specimens 
are as follows: 
shell opercular plates 
specimen diameter lateral diameter height height scutum height tergum 
1 23.8 18.9 14. 0 5.9 6.9 
2 19.1 15.0 ie}, ag2 6.1 
3 2050 18.7 Hoe A 6.2 Uo ® 
4 23.4 15.9 NG 7 6.8 Cell 
Both the scutum and tergum are tinted apically, either pink or 
pale purplish blue. The articular ridge of the scutum is about two- 
thirds the length of the articular margin, and it terminates in an 
acute point. In young stages the adductor ridge is prominent, acute, 
and it extends nearly to the midpoint of the basal margin, but in 
older specimens it is less prominent and less broadly rounded. The 
adductor muscle depression is deep, and its outline varies from 
elongate-oval to oval, to nearly circular. 
The tergum is broad, triangular, and thinner than the scutum. 
The spur is separated by about its own width from the basiscutal 
angle. Externally, the longitudinal furrow is commonly closed but 
sometimes open. Crests for the attachment of the tergal depressor 
muscles are weakly developed, and few in number. 
On each side of the deeply notched crest of the labrum there are 
three teeth (fig. 3d). Interspersed among the teeth and extending 
laterally the complete length of the crest, there are short, soft setae. 
Extending obliquely from the superolateral margin on each side of 
the crest toward the basicentral portion of the labrum, there are 
