1902.] CRUSTACEA OF THE " SKEAT EXPEDITIOX." 369 



Log. Pulau Bidan, Penang. Two females, one with ova. Also 

 another female, from JVeris, with a small Ascidian attached to 

 the left sides of the 2nd and 3rd abdominal segments. 



20. CCEXOBITA PERLATUS M.-Edw. 



Coenohita perlatits M.-Edw. Hist. Kat. Crust, ii. p. 242 (1837); 

 Miers, 'Alert' Crust, p. 555 (1884). 



Log. ? Three females, from M'urex. 



Miers has noted (/. c. supra) the fact that in this species " there 

 is an oblique row of somewhat more elongated tubercles on the 

 upper surface of the palm, occupying the place of the sei-ies of 

 oblique ridges in C. rugosa " ; such an arrangement I find in 

 these three specimens. But the specimens in question being 

 somewhat small, the tubercles on the legs are noticeably less 

 prominent and less pearly than in typical examples ; the carapace 

 also is less rugose. 



B. CIRRIPEDIA. 



X. Genus Balanus da Costa. 



21. Balanus amphitrite Darwin, 



Balanus anipliitriie Darwin, ' Balanidte,' p. 240, pi. v. (1854). 



Log. Patani. On pieces of wood, var Gomimtnis ; on Miirex, 

 var. obscurus ; on Lamellibiunch shells, var. niveus. 



Log. Singora. On Lamellibranch shells, var. ohsGurus, and 

 var. 7iiveus. 



22. Balanus Amaryllis dissimilis, subsp. nov. (Plate XXXIV. 

 figs. 3-3 G.) 



% Balanus amaryllis 'v?a^.'i Weltner, Ai-ch. f. ISTaturg. Ixiii. 1, 

 p. 270 (1897). 



Cf . Balanus amaryllis Darwin, ' Balanidse,' p. 279, pi. vii. fig. 6 

 (1854); Hoek, ' Challenger ' Cirripedia, p. 153 (1883). 



Log. Kota Bharu, Kelantan. 



This subspecies is represented here by two distinct forms : one, 

 the subspecies itself, of which thei-e ai-e seven large examples ; 

 the other a colour-variety, of which there are several smaller 

 examples, attached to pieces of a Gorgonian. These two forms 

 well illustrate the difficulty, which must sometimes arise, of 

 finding a satisfactoiy place in the binomial system of nomen- 

 clature for certain divei'gent forms. Thus, in the pi-esent instance, 

 No. I., though Glosely allied to the species B. amaryllis, yet 

 shows sufficiently divergent structural characteristics to be ranked 

 as a distinct variety, if considered alone. But the presence of 

 No. II. necessitates some sort of modification of this conception ; 

 for, while exhibiting the same structural divergence, it also 

 differs in colour arrangement : thus it becomes incumbent to 

 form either a subvariety for No. II., or a subspecies for No. I. 

 And in view of the fairly numerous instances in which Darwin 

 has considered colour differences as of varietal worth (vide, e. g., 



Proc. Zool. Soc— 1902, Vol. II. No. XXIV. 24 



