OUBICULA. 389 



Of the genns Crania, few authors have acknowledged 

 more than one recent species, but M. HoeninghauSj of Cre- 

 fekl, asserts that two or three different species have been 

 referred to the Crania personata. Neither cardinal pro- 

 cesses, nor any indication of a hinge, pertain to the shell 

 of this genus. The interior exhibits muscular impressions ; 

 the exterior appears compressed, somewliat square, inequi- 

 valve, with an upper convex and patelliform valve, and a 

 lower one flat and attached. 



The genus Orhicula is pecuHar in the composition of its 

 shells j they are rather horny than calcareous, and differ in 

 their mode of attachment. Although fixed immediately to 

 marine substances, one upon the other, they do not adhere 

 by any portion of the shell, but rather by means of a car- 

 tilaginous tendon passing through a longitudinal fissure, 

 situated in the centre of a small oval depression, pertaining 

 to the lower valve, and which immediately afterwards ex- 

 pands and conceals the edges. 



Love delighteth in small doings j — it is best shown in 

 those little acts of kindness that form the joy of life. We 

 have thought, when considering the wonderful construction 



