CLASS II. BRACHIOPODA. FAMILY 2. ADH.ERENTIA. 185 



CRANIA, Brugmere. 



Testa compressa, subquadrata, inasquivalvis, aequilateralis ; valvis, supe- 

 riore convexa, patelliformi, inferiore planulata, subtus aftixa, facie 

 interna impressionibus muscularibus quatuor distinctis profunde 

 imbuta, quarum dua? subcentrales approximatae. Cardo nullus. 



The Anomia craniolaris of Linnaeus was selected by Bruguiere for the 

 formation of the present genus : although unacquainted with the animal 

 inhabitant, he did not fail to recognise a resemblance in its shell to that 

 of the Brachiopoda, for in the ' Encyclopedic Me'thodique ' he figures it 

 in the exact situation which it is now destined to occupy. The animal of 

 Crania has, however, been both described and figured by Poli under the 

 title of Criopus ; and the fact of its having been confounded by Lamarck 

 with that of Orbicula, accounts for some hesitation on the part of the last- 

 named author in not including the present genus in his family of ' Les 

 Brachiopodes,' " mais V animal e't ant inconnu, nous ne pouvons savoir sic' est 

 un Brachiopode." It is certainly much to be regretted that Professor 

 Owen did not succeed in obtaining the soft parts of Crania, when engaged 

 with the dissection of Terebratula and Orbicula ; Sowerby, however, has 

 given his testimony of the presence of the spiral arms, and there is there- 

 fore little doubt of the accuracy of the situation to which this genus is 

 now assigned. Few authors have acknowledged more than one recent 

 species ; but M. Hceninghaus of Crefeld, who has given much attention 

 to the identification of the Craniae, asserts that two or three different 

 species have been referred to the Crania personata. 



The shell of Crania is described as being compressed, somewhat square, 

 inequivalve, and equilateral ; the upper valve is convex and patelliform, 

 the low T er flat and attached. The interior of the latter exhibits four very 

 distinct muscular impressions, two of which are subcentral and approx- 

 imate. There are no cardinal processes, nor any indication of a hinge. 



vol. i. 2 b 



