10 FOSSIL CIRRIPEDIA. 



justified in giving short names to each of the more important valves, these being common 

 to the Pedunculated and Sessile Cirripedes. 



The title of peduncle, which is either naked or squaraiferous, requires no explanation ; 

 the scales and lower valves are arranged in whorls, which I have called by the botanical 

 term of Verticillus. The part supported by the peduncle, and which is generally, though 

 not always, in recent species protected by valves, I have designated the Capitulum. 



I have applied the term Scutum to the most important and persistent of the valves, and 

 which can almost always be recognised by the hollow giving attachment to the adductor 

 scutorum muscle, from the resemblance which the two valves taken together bear to a shield, 

 and from their office of protecting the front side of the body. From the protection afibrded 

 by the two Terga to the dorso-lateral sm'face of the animal, these valves have been thus 

 called. The term Carina is a mere translation of the name already used by some authors, 

 of Keel- Valve -. in the genus Scalpellum, in which this valve is taken as typical, 1 have 

 found it quite necessary, with fossil specimens, to distinguish the roof (see Woodcut, I,) 

 or exterior surface, as the tectum (A) ; the inflected sides, as the parietes (B) ; and in 

 several species in the upper half of the valve, the intra-parietes (C) : the expressions of 

 apex, basal margin, and inner margin, as applied to the Carina, require no explanation. 

 The rostrum has been so called from its relative position to the Carina or keel. There is 

 often a sub-carina and a suh-rostrum. 



The remaining valves have been called Latera ; there is always one large upper one 

 inserted between the lower halves of the Scuta and Terga, and this I have named the Upper 

 Latus or Latera ; the other Latera in PoUicipes are numerous, and require no special 

 names ; in Scalpellum, where there are at most only three pair beneath the Upper Latera, 

 it is convenient to speak of them {vide Woodcut, I,) as the Carinal, Infra-median, and 

 Rostral Latera. 



As each valve, especially amongst the fossil species, requires a distinct description, I 

 have found it indispensable to give names to each margin. These have mostly been 

 taken from the name of the adjoining valve, (see Woodcut, L) In PoUicipes the margin 

 of the Scutum adjoining the Tergum and Upper Latus, is not divided (Woodcut, II,) into 

 two distinct lines, as in Scalpellum, and is therefore called the tergo-lateral margin ; a 

 narrow portion or shp along this side of the valve may be seen (Woodcut, II,) to be formed 

 of upturned lines of growth ; this is often of service in classification, and I have called it 

 the tergo-lateral shp or segmentum tergo-laterale. In Scalpellum (Woodcut, I,) these two 

 margins are separately named Tergal and Lateral. The angle formed by the meeting of 

 the basal and lateral or tergo-lateral margins, I call the baso-lateral angle ; that formed by 

 the basal and occludent margins, I call, from its closeness to the Rostrum, the rostral 

 angle. In PoUicipes the Carinal margin of the Tergum (Woodcut, III,) can be divided into 

 an upper and lower Carinal margin. 



That margin in the Scuta and Terga which opens and shuts for the exsertion and 

 retraction of the cirri, I have called the Occludent margin. 



