78 
Memoirs of the Indian Museum. 
[VOL. 
Subgenus Hyalolepas, nov. 
Lepas tenuivalvata (Annandale). 
Dichelaspis tenuivalvata, Annandale, Spolia Zeylanica, iii, p.-i93, figure (1906) ; 
bepas tenuivalvata, id., in Herdman’s Report on the Marine Biology of Ceylon 
(Roy. Soc.), pt. V, Cirripedia, p. 139 (1906). 
The only known species of this subgenus was described in 1906 by myself as 
Dichelaspis tenuivalvata ; in the same year (see synonymy above) I transferred it to 
the genus Lepas. The specimens were found attached to a sea-snake taken off the 
coast of Ceylon, and the species is evidently adapted to a pelagic life. I am now not 
at all sure that I was right in regarding the specimens as immature ; in any case the 
lack of calcification exhibited by the valves is not due to immaturity. 
Diagnosis — 
Capitueum transparent, strongly compressed, flat on the surface ; carinal margin 
rounded ; occludent margin sinuous, slanting outwards from above ; lower margin 
straight, horizontal ; aperture large. Valves very imperfectly calcified, transparent, 
only the tergum and the upper part of the scutum and carina having a definite 
outline. Carina forked below, with two long basal branches, the distal parts of which 
disappear gradually without definite outline ; the dorsal branch narrow, somewhat 
irregular in outline, often bearing a short tooth on the outer surface near the tip, 
which is situated nearer the apex than the base of the tergum ; no ridge on the external 
surface. Tergum with the carinal and scutal margins nearly equal, each more than 
three times as long as the carinal margin ; the apical angle rounded. Scutum separated 
narrowly from the tergum and carina, large but with only its tergal margin at all well 
defined, gradually disappearing towards the base of the capitulum, so that its lower 
limits cannot be detected exactly. 
Peduncle very short, less than a quarter as long as the capitulum, transparent, 
irregularly annulated. 
Cirri, etc. — First cirrus with both branches rather narrow, the posterior being 
shorter than the anterior by about four joints. The anterior branch with 14 joints, 
having the anterior margin of each joint nearly straight and the posterior margin 
boldly convex ; the last six joints bear at the distal extremity of their posterior 
margin a pair of short spines ; the distal joint terminates in a crown of longer and 
slenderer bristles, while the anterior margin of each joint bears a dense fringe of long 
hairs. The posterior ramus barely stouter than the anterior at the base ; the distal 
joint ending in a fine bristle; the four penultimate joints bearing short spines on their 
distal extremity on and near the posterior margin , the number of these spines differ- 
ing on the different joints and probably variable. Remaining cirri not very widely 
separated from the first pair, moderately long, slender ; the distal joints (six to ten) each 
bearing several short spines at the distal extremity of the posterior margin, with a 
bunch of bristles at the tip of the last joint ; the anterior margin of each joint with a 
dense fringe of bristles and hairs. Ä 7 ial appendages each consisting of a single claw- 
