15 



birds wcre concerned, tlie geographical distiibution of allied or 

 identicalsjiecies, lie directed Iiis observations chiefly to tlie deter- 

 mination of tliose North American Birds vvhich seemed to him to be 

 referrible to European species, and of those which, having been 

 generally considered as identical with European, appeared, on di- 

 rect comparison, to present difFerences in form and colouring. 



The common TurnstoJie of Europe, Strepsilas coUaris, Temm., 

 appears to be not oniy identical with the Turnstone of North Ame- 

 rica, but to be spread, without any tangible variation, over almost 

 every portion of the globė. 'Yhe Sanderling, Calidris arenaria,Temm., 

 and the Knot, Tringa Canutus, Linn., are also identical in both 

 continents ; as is the great luhite Heron or Egret, Ardea Egretta, 

 Temm. The common Tern or Sea-Sivallotv of England, Sterna 

 Hirundo, Linn., occurs equally in North America. The cojnmon 

 Crou), Corvus Corone, Linn., is also identical in both continents. 



With respect to the IVkimbrel, Numenius phcsopus, Temm., and 

 the little Sandpiper, Tringa TemmincUi, Mr. Gould stated himself 

 to be unable to determine as to their identity without the compari- 

 son of more specimens frora America than be had yet been able to 

 obtain for the purpose of examination. 



The Cross-bill of North America Mr. Gould showed to be very 

 distinct from that of Europe, the Loxia curvirostra, Linn, ; it is 

 one third less in all its proportions, and is somewhat less brilliant in 

 colouring. The Ring Dottrel of North America is also specifically 

 distinct from that of Europe, the Charadrius Hiaticula, Linn. ; in- 

 dependently of difFerences in admeasureraent, its seraipalmated foot 

 will always serve to distinguish it. 



In addition to the Birds that have been already mentioned, Mr. 

 Folliott's coUection contained a series of the Sylviadco of the United 

 States, Severai Fly-calchers, the Orphea riifa, &c., &c. 



Mr. Gray exhibited specimens of the shelly covering of a Radiated 

 animal, allied to the EchinidcE and the Asteriidce, which be regarded 

 as the type of a new genus, and for which he proposed the name 

 of 



Ganymeda. 



Corpus heraisphaericum, depressura ; depressione dorsi centrali 

 quadrangulari. 



Os inferum, centrale. 



Anus nulius. 



Ambulacra nulla. 



" The body is hemispherical, depressed, thin, chalky and hollow. 



«' The back is rounded, rather depressed, flattened behind, with a 

 rather sunk quadrangular centrai space. 



" The sides are covered with sunken angular cavities with a small 

 round ring, having an oblong transverse subcentral hole in their 

 base. 



•' The under side is small, rather concave, with five slight sloping 

 elevations from the angles of the mouth to the angles of the rather 

 Pentagonai margin. The edge is siraple. 



