NOMENCLATURE. 



not any limbs, and is as plainly articulated as the larva 

 of a fly ; it is entirely naked, without valves, carapace, or 

 capitulum, and is attached to the Cirripede, in the sack 

 of which it is parasitic, by tivo distinct threads, terminating 

 in the usual larval, prehensile antennae. I intend to call 

 this Cirripede, Proteolepas. I mention it here for the sake 

 of calling attention to any parasite at all answering to 

 this description. 



Although the present volume is strictly systematic, I 

 will, under the general description of the Lepadidee, give 

 a very brief abstract of some of the most interesting 

 points in their internal anatomy, and in the metamor- 

 phoses of the whole class, which I hope hereafter to treat, 

 with the necessary illustrations, in detail. I enter on the 

 subject of the metamorphoses the more readily, as by this 

 means alone can the homologies of the different parts be 

 clearly understood. 



On the Names given to the different parts of Cirripedes. 



I have unwillingly found it indispensable to give 

 names to several valves, and to some few of the softer 

 parts of Cirripedes. The accompanying figure of an 

 imaginary Scalpellum includes every valve ; the two most 

 important valves of Lepas are also given, in which the 

 direction of the lines of growth and general shape differ 

 from those of Scalpellum as much as they do in any genus. 

 The names which I have imposed will, I hope, be thus 

 acquired without much difficulty- 



Whoever will refer to the published descriptions of 

 recent and fossil Cirripedia, will find the utmost confusion 

 in the existing nomenclature : thus, the valve named in the 

 woodcut the Scutum, has been designated by various well- 

 known naturalists as the " ventral," the " anterior," the 

 t( inferior," the " ante-lateral," and the " latero-inferior" 

 valve ; the first two of these titles have, moreover, been 

 applied to the rostrum or rostral valve of sessile Cirripedes. 



