INTRODUCTION. 



NOMENCLATURE OF THE VALVES. 



Figure II. 

 Scutum of POLLICIPES. 



Apex. 



Figure I. 

 CAPITULTJM. 



Occludent 

 margin. 



Ter!;o- 

 lateral ' 

 mai'gin. 



Basal 

 margin. 



Tergum. .■ 



Scuttun. 



Bostnim. 



Sub-rostrum. 



Carina. 



Sub-carina. 



Rostral Infra- Carinal 



Latus. . median Latug. 



Latus. 



PEDUNCLE. 



N.B.— In the Carina of Scalpellum, 

 A 13 the tectum ; B the parietes ; C the intra-.parietes. 



Figure III. 

 Tergum of pollicipes. 



Occludent 



margin.. 



Scutal 



Apex. 



angle. 



Upperv 



Lower 



Carinal 

 I margin . 



Whoever will refer to the pubhshed descriptions of recent and fossil Cirripedia, will 

 find the utmost confusion in the names given to the several valves ; thus, the valve named 

 in the above woodcut, the Scutum, has been designated by various well-known naturalists as 

 the " ventral," the " anterior," the " 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. The Tergum has been called the " dorsal," the " posterior," the 

 " superior," the " central," the " terminal," the " postero-lateral," and the " latero-superior" 

 valve. The Carina has received the first two of these identical epithets, viz. the " dorsal" 

 and the "posterior;" and hkewise has been called the "keel-valve." The confusion, 

 however, becomes far worse, when any individual valve is described, for the very same 

 margin which is anterior or inferior in the eyes of one author, is the posterior or superior 

 in those of another ; it has often happened to me that I have been quite unable even to 

 conjecture to which margin or part of a valve an author was referring. Moreover, the 

 length of these double titles is inconvenient. 



Hence, as I intend to describe all the recent and fossil species, I have thought myself 



b 



