CIRBIPEDIA. 139 



DESCRIPTION OF THE SPECIES. 



LEPADID.E. 

 *Lepas anatifera, L. 



Localities : Galle (on a buoy rope) and Cheval Paar, Gulf of Manaar. 



Several of the specimens from the Cheval Paar belong to Darwin's var. A. 



It is often almost impossible to distinguish tropical examples of this species from 

 L. anserif&ra by mere examination of the shell. The pale colour of the upper part 

 of the peduncle is a good diagnostic character of the latter, but one which cannot 

 always be detected in faded or shrunken specimens. The only safe method of distin- 

 guishing the two species is to examine the filamentous appendages. 



L. anserifera appears to be more abundant in the Bay of Bengal than L. anatifera. 

 So far as my experience goes, examples of both species from the Indian region are 

 generally small; indeed, it seems probable that they do not reach the same dimensions, 

 except very occasionally, as those attained by individuals reared in higher latitudes. 

 Their stalk, especially, is frequently stunted. 



Lepas tenuivalvata (Annandale) (14). 



In my account of this species (as Dichelaspis tenuivalvata) I did not describe the 

 jjenis or the anal appendages. Having now been able to dissect a specimen in detail. 

 I am in a position to give an account of these organs. The penis is long, slender, 

 tapering, with a few scattered hairs on its surface. The anal appendages are 

 uniarticulate, claw-shaped, and naked. Taking these characters into account, the 

 species should probably be placed in the genus Lepas. In placing it in Dichelaspis, 

 1 relied chiefly on the shape of the carina. The specimens are probably immature, 

 but the shape of this valve distinguishes it from any other representative of the 

 former genus. 



Dichelaspis equina, Lanchester (8). 



Some doubt as to the difference between this species and Gray's Octolasmis 

 warwickii is hinted at by Gruvel (10). The most constant external character 

 of the former is the division of the carina into two parts by a horizontal cleft near 

 tin' base of the capitulum. 1 have now examined a large number of specimens, 

 which vary greatly as regards the shape of the terga and the transparency of the 

 membrane, and all agree in this respect. It seems to be a good specific character ; 

 but two distinct forms have probably been confused, if Darwin's figure (1) is correct, 

 under the name D. warwickii (see figs. 2 and 3). 



T 2 



