126 Mr. L. Reeve on the recent Craniae. 



close, rather prominent cells, which are more abundant on cer- 

 tain parts of the branches, and form roundish nodules. 



This species may be named Paragorgia Johnsoni, after its 

 discoverer. 



Hab. Madeira. 



XV. — A Revision of the History, Synonymy, and Geographical 

 Distribution of the recent Cranise and Orbiculae. By Lovell 

 Reeve, F.L.S., F.G.S. 



1. Crania, Retzius. 



The shell of this Brachiopod was first known in a fossil state. 

 The calcifying functions of the animal are exercised chiefly by 

 the under lobe of the mantle, for the secretion of a thickened 

 adherent valve, unconnected by any hinge or ligament with the 

 upper valve ; and, before the time of Linnaeus, it was named 

 Nummus, and sometimes Nummulus Brattenburgensis, " B ratten - 

 burgh money." Linnaeus and Chemnitz still confounded recent 

 and fossil specimens together ; and the separation of the valves 

 led naturalists, among whom were Miiller and Montagu, to de- 

 scribe them as Limpets. A curious character in the adherent 

 valve of this genus, and which seems to have attracted the at- 

 tention of Linnaeus, is a similitude, in the configuration of the 

 internal muscular scars and protuberances, to a human face. A 

 little above the centre a raised callosity, termed the rostellum, 

 forms the nose, and the scars of the two posterior adductor 

 muscles of the animal give the resemblance of a pair of eyes, 

 while the anterior thickened rim serves for the outline of the 

 cheeks and chin. This fanciful representation suggested to 

 Linnaeus the name Anomia craniolaris ; and Crania was soon 

 afterwards proposed by Retzius to separately distinguish the 

 group. 



Defrance described several fossil species of Crania. The first 

 special monograph of the genus which included the recent spe- 

 cies was made, in 1828, by M. Hbninghaus of Crefeld. Since 

 that period, the Crania have been ably studied by Sowerby, 

 Deshayes, Davidson, and Suess ; and, although little has been 

 added to our knowledge of the species, some interesting parti- 

 culars have been collected of their geographical and bathymetrical 

 distribution and their bearings on geological phenomena. The 

 revision which I propose to make of the synonymy will be indi- 

 cated in the following analysis of the species. Only four recent 

 species have been collected. C. anomala, of our own coast, the 

 best-known species of the genus, ranges from Spitzbergen, in 

 the north of Europe, to Vigo Bay, in the south. Here it stops. 



