go Memoirs of the Indian Mitseum. [Voi.. II, 



Subgenus PcECir.ASMA, Darwin. 

 Pœcilasma kcem-pferi, Darwin. 



P. ksempferi, Darwin, Mon. Cirr., lyCp., p. 102, pi. ii, fig. i ; Gruvel, Zool. Travail- 

 leur et Talisman, Cirrhipèdes, p. 46, pi. iv, fig. i ; Weltner, Archiv, f. Naturg., 

 1897 (i), p. 243 ; Pilsbry, Bull. Bureau of Fisheries, vol. xxvi (1907), p. 183, 

 ^nà Bull. U. S. Nat. Mus., No. 60, p. 84, pi. vi, figs, i — 5, 13 and 14; 

 Annandale , Illustr. Zool. " Investigator," Crust. Bnt., pi. iii, fig. i. 



P. aurantium, Darwin, op. cit.^ p. 105, pi. ii, fig. 2 ; Hoek, Siboga-Exped., Mon. 

 xxxia, Cirr. Ped., p. 7. 



P. dubium, Hoek^ op. cit., p. 6, pi. i, figs. 2 — 4, pi. x, figs. la — d. 



CapituIvUM more or less narrowly ovate ; the carinal margin much more strongly 

 arched than the occludent margin; apex pointed, valves five, stout, closely approxi- 

 mate. Ter gum triangular ; the carinal angle slightly truncated, the others sharp ; 

 the scutal margin straight. Carina arched, ending in a very small and imperfect disk 

 at the base, tapering above, almost of the same width throughout or widest at the 

 base ; above extending a short distance between the terga. Scutum entire, much 

 longer than broad, with a more or less distinct ridge running down it near the 

 occludent margin ; internal umbonal teeth feebly developed or strong. 



Pkduncle slender, variable in length, ringed, naked. 



Cirri, etc. — Rami of first cirrus nearly equal ; second cirrus widely separated 

 from first. Anal appendages about 4- length of the pedicel of the sixth cirrus, with 

 bristles at the tip and down the whole of the posterior margin. Penis long, stout, 

 hairy. 



Mouth parts. — Mandibles variable. Maxilla has "two large upper spines, the 

 edge deeply notched below them, sparsely spiny in the notch. It then protrudes and 

 is rather closely set with spines " (Pilsbry). 



Several forms have been described which seem to be subspecies or local races of 

 P. kcBmpferi. The Indian specimens I have examined do not quite agree with any 

 figure I have seen. Unfortunately I have only been able to examine six individuals 

 from any Oriental locality. All of them were taken in the Gulf of Manaar on the 

 shell of a '' spinose crab" {Echinoplax pungens) at a depth of nearly 500 fathoms. 

 They come nearest to the form recently described by Hoek as P. dubium, but their 

 carina is intermediate between that of this form and that of the specimen figured by 

 Darwin. Pilsbry' s figure, however, of the carina of a Japanese specimen does not 

 altogether agree with Darwin's, although the latter's specimen was also from Japan. 

 In my specimens the occludent margin projects less beyond the vertical ridge on the 

 scutum than it does in Hoek's figure, but a little more than it does in Darwin's. On 

 the whole, I think that it is possible to distinguish five local races of the species, and 

 that they may be distinguished as follows : — 



Race I (typical form). — A single vertical ridge on the scutum. Occludent margin 

 of the scutum projecting very little beyond the vertical ridge, evenly curved ; 



