244 SHELLS AND SHELL-FISH. PART I. 



side of the circle we are now tracing, and consists of all 

 those simple cup-shaped shells which have a defined apex 

 or top^ hut without any hasal or internal support. They 

 adhere to rocks, and by their broad and fleshy foot retain 

 such a firm hold as not to be separated without great 

 art or violence. The animal very much resembles that 

 of Hipponyx; for Cuvier says it has a short and thick 

 snout, two distinct and pointed tentacula, and the eyes 

 placed at the base. The most important sub-genus 

 yet determined is Siphonaria Sow., which, with that 

 inconsistency and violation of all natural affinities which 

 pervades the greater part of this class, as exhibited in 

 the Regne Animal, is actually placed in a different order, 

 between Calyptrcea and Sigaretus ! Every one accus- 

 tomed to contemplate the beautiful order and gradation 

 of nature, must be shocked at such a violation of natural 

 affinity as this arrangement exhibits. It is the more 

 inexcusable, because it is neither sanctioned by any re- 

 semblance whatever between the shells or their animals 

 of the genera thus confusedly mixed. Siphonaria, in 

 short, is that link which connects the Scutihranchia 

 with the Cyclobranchm ; for, like these latter, according to 

 Cuvier's own showing, " the tentacula seem to be want- 

 ing, the head being merely furnished with a narrow 

 veil j" so that, if these organs really exist, they must be 

 but mere vestiges. Here, then, is probably the last 

 form of the Scutihranchia ; and it occurs exactly at that 

 point of the circle which, from theory, could be next to 

 the Cyclobranchia. 



(228.) But there is yet another form to be added : 

 this is our new genus Pedicularia (^(/. 44.), which 

 appears never to have been described by any writer. In 

 its somewhat patelliform shape it resembles a Patella ; 

 yet, although always oval, its form is irregular, since 

 its circumference is adapted to the inequalities of the 

 substance to which the animal adheres : hence, to an 

 inexperienced eye, the margin would appear broken : its 

 substance, however, is strong, like that of a Hip- 

 ponyx, from which and from Patella it essentially 



