123 



that size, which was most efficient of all for subaquatic progression; 

 species of an intermediate character of course never occurring. It 

 was obvious that a high standard of respiration is necessary to enable 

 the Puffin and its allies to maintain aerial flight with their short and 

 narrow wings : and the great development of the lateral air-cavi- 

 ties in these birds, incidentally remarked by Mr. Ord (in his conti- 

 nuation of Wilson's Ornithology) in the particular instance of the 

 Rotche, he believed bore reference to that especial object. Mr. Blyth 

 also called attention to the resemblance of the Puffin's mode of flight 

 to that of a Beetle, and stated that its actions when under water so 

 much resembled those of the Dt/ticidce, that whoever had seen the 

 one could form a quite accurate notion of the other ; the bird ad- 

 vancing solely by means of the wings, and the insect making use of 

 only its middle pair of legs to oar itself along ; a further striking 

 resemblance was pointed out in this exterior conformation, being a 

 beautiful instance of analogy or adaptation of two extremely dissi- 

 milar types to the same mode of life. 



Mr. Gray communicated to the Meeting the following arrangement 

 of the Sorices, accompanying his observations upon this group by 

 the exhibition of the shrews in the Society's collection. 



Mr. Gray remarked that Wagler, in the Isis for ] 832, divided the 

 European shrews into three genera, according to their habits and 

 the structure of their teeth; and Duvernoy in 1834 or 1835, over- 

 looking the natural characters pointed out for the groups by Wagler, 

 divided them into artificial genera according to the size and form of 

 the cutting teeth. On examining the species in the British Museum, 

 Mr. Gray found it necessary to further divide them in the following 

 manner ; the various groups forming a series returning into itself. 



A. Land Shrews. Tail simple, feet not ciliated on the sides. 



1. Corsira. — Front lower cutting teeth sharp-edged, and toothed 

 above : tail with short close-pressed hairs. 



2. Myosorex. — Front lower cutting teeth sharp-edged, entire above : 

 tail with short close-pressed hairs. 



3. Sorex. — Front lower cutting teeth rounded, and simple above : 

 tail with short hairs and longer scattered bristles. 



B. Water Shrews. Tail loith a series of bristles beneath : feel 



and toes ciliated on the sides. 



4. Amphisorex Front lower cutting teeth simple : 4 hinder cut- 

 ting teeth gradually smaller, hinder very small. 



5. Crossopus. — Front lower cutting teeth sharp-edged, and toothed 

 above : hinder cutting teeth rapidly smaller. 



1. Corsira, Gray. /S'orea;, Wagler? /T^/rfrosorea; part, Duvernoy*, 

 Head elongate, muzzle slender, produced ; ears hid in the fur. 

 Tail elongate, slender, when young round, becoming quadrangular, 

 covered with short, rigid, close -pressed hairs, (not ciliated,) ; feet 

 simple, not ciliated ; front wrist bearded beneath. Skull elongate. 

 Teeth coloured ; cutting teeth ^, large, two upper central, strong, 



• Since these observations were made, M. Duvernoy has transferred his 

 name of Ilydrosorex to the group which he had formerly named Amphisorex, 

 and vice versd. The references in the text are to his earlier arrangement. 



