72 Memoirs of the Indian Museum. [Vol. II, 



(b) Lateral appendages numbering 2 ; anal appendages multi- 

 articulate ; not more than one pair of valves .. Heteralepas. 



Genus I,epas, Linné (1767). 

 The inclusion in the genus of Lepas tenuivalvata renders it necessary to modify 

 the description of the genus a little, but I have no doubt as to the propriety of adopt- 

 ing this course. The possession by the species in question of filamentous appendages, 

 the structure of its anal appendages, mandibles and maxillae and the form of its 

 valves, so far as this is perceptible, ally it indubitably to Lepas if considered together, 

 while the curious modification in structure exhibited by its shell is clearly an adapta- 

 tion to a mode of life somewhat unusual in the genus. It may be convenient, however, 

 to regard it as the type of a new subgenus, for which I propose the name Hyalolepas. 

 I am of the opinion, with Pilsbry and other writers on the Cirripedia, that Lepas fascicu- 

 laris, Ellis and Solander, should also be considered as representing a subgenus 

 distinct from that of the typical Lepas; Gray's name Dosima may be used for the 

 former while the latter may be called Anatif a, Brugière, for it is desirable to avoid the 

 duplication of names as regards subgenera when possible. 



The genus and its subgenera may therefore be diagnosed as follows : — 

 Genus Lepas, Linné (1767). 



Lepadidœ with five valves, which are usually well calcified and more or 

 less approximate; the carina extending between the terga above, 

 terminafng below in an embedded fork or an external disk ; scuta 

 triangular or sub triangular, with their umbones at the rostral angle. 

 Lateral appendages usually present ; anal appendages consisting of 

 a single joint, uncinate; without long hairs. Mandibles with five or six 

 teeth ; maxillœ with the free edge scalariform. Peduncle usually well 

 developed, naked, or provided with chitinous plates. 

 Subgenus Anatif a, Brugière (1789). 



Valves fully calcified, usually opaque; base of the carina forked, 

 the branches of the fork being short or widely extended. 

 Subgenus Dosima, Gray (1825). 



Valves fully calcified but translucent ; base of the carina expanded 

 into an external disk. 

 Subgenus Hyalolepas, nov. 



Valves barely calcified ; the umbones indistinct ; carina forked at the 

 base, the branches of the fork, so far as they are distinguishable, 

 being long and almost parallel to one another. 



Subgenus Anatifa, Brugière. 



Seven species of this subgenus have been described, of which five are common 

 and widely distributed, while two are rare or possibly have a restricted geographical 



