15 



birds were concerned, the geographical distribution of allied or 

 identical species, he directed his observations chiefly to the deter- 

 mination of those North American Birds which seemed to him to be 

 referribie 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 Turnstone of Europe, Strepsilas collaris, Temm., 

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

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

 every portion of theglobe. The Sanderlhig, Calidris arenaria,Hemm., 

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

 continents ; as is the great white Heron or Egret, Ardea Egrelia, 

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

 Hit-undo, Linn., occurs equally in North America. The common 

 Crow, Corviis Corone, Linn., is also identical in both continents. 



With respect to the JVhimbrel, Nume?iius phceopics, Temm., and 

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

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

 son of more specimens from America than he 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 admeasurement, its semipalmated foot 

 will always serve to distinguish it. 



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

 Folliott's collection contained a series of the Sylviadce of the United 

 States, several Fly-catchers, the Orphea riifa, &c., &c. 



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

 animal, allied to the Echinida and the Asteriida, which he regarded 

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

 of 



Ganymeda. 



Corpus hemisphflericum, depressum ; depressione dorsi centrali 

 quadrangulari. 



Os inferum, centrale. 



Anus nullus. 



Ambulacra nulla. 



•' The body is hemispherical, depressed, thin, chalky and hollow. 



" The back is rounded, rather depressed, flattened behind, with a 

 rather sunk quadrangular central 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 

 pentagonal margin. The edge is simple. 



