Zoological Society. S83 



species, but if he can find no other difference except that which 

 exists in their dimensions, let him consider the one a giant, the other 

 a dwarf. Let it be remembered that among the Cyprcecz it is not un- 

 common to observe young shells of three inches in length, and fully 

 grown ones of the same sort only one inch in length ; likewise, of 

 the well-known British Pholades there are individuals quite in a 

 young state of two inches in length, and perfectly formed shells of 

 the same species not more than half an inch long. For an instance 

 in demonstration I need only refer to the Phol. papyraceus, so 

 abundant at Torquay, of which the young shells have been considered 

 by many as a distinct species and have been named by Dr. Turton 

 Phol. lamellosus. This varies in size exceedingly, so that it may 

 be obtained both in an incomplete and young state and in a fully 

 grown condition from half an inch to nearly two inches in length. 

 The circumstance of its having rarely occurred in an intermediate 

 state of growth, when the anterior opening is only partly closed 

 and the accessory valves only partly formed, led Dr. Turton and 

 others to persist in regarding the young and old as two distinct 

 species. Other similar instances will be shown in the course of the 

 present concise account of some hitherto undescribed species of the 

 same genus brought to England by Mr. Cuming." — G. B. S. 



Pholas crvciger, Chiloensis, var. parva, subtruncata (very like 

 our British Pholas parva), calva, Gray, MSS., calva, var. nana, acu- 

 minata. 



One specimen of the last-named shell in Mr. Cuming's collection 

 merits particular notice. It demonstrates a fact of considerable im- 

 portance to geologists. It is in argillaceous limestone, very much re- 

 sembling lias, and in forming the cavity in which it resides, it has, 

 by such chemical process as frequently takes place, absorbed a much 

 greater quantity of the rock than could be retained or converted ; 

 this is again deposited at the upper part of the cavity; and thus the 

 rock is recomposed. — G. B. S. 



Phol. melanura, tubifera (resembling in a marked manner the 

 Pholas papyracea of Southern Devonshire), Quadra, Quadra, var. 

 (with the epidermis which covered the muscle contained in the con- 

 cave reflected anterior dorsal margin changed into calcareous matter), 

 curta, and cornea. 



The whole of the Toucans of the Society's collection were exhi- 

 bited in illustration of an account given by Mr. Gould, at the re- 

 quest of the Chairman, of the species of Ramphastos, 111., and Ptero- 

 glossus, Ej., constituting the family Ramphastida. Mr. Gould's 

 attention having been of late particularly directed to this family in 

 the preparation of a Monograph of it, illustrated by coloured figures 

 of all the birds comprised in it, he was enabled to state the existence 

 of the under-mentioned species of the Fam. Ramphastid^e, Vig. 

 Rostrum magnum, ad basin nudum ; tomiis serratis. Lingua pecti- 

 nata. Pedes scansorii. 



Genus Ramphastos, ///. Ramphastos (pars),Xmw. Rostrum max- 

 imum. Nares frontales, prope basin maxillae sitae. Cauda aequalis. 



Nigri, torque pectorali tectricibusque caudae inferioribus coccineis , pe- 



