Mr. Swainson on seneral new groups in Ornithology/, 343 



to conduct the water to the branchiae. This genus seems to be 

 the connecting link of those animals which have the aperture of 

 their shells entire, with those that are channeled ; in fact it may 

 be considered as the commencement of the Zoophagiy having 

 shells with a canal at their base (though here it is scarcely per- 

 ceptible), and which is continued and becomes more developed ia 

 the Cerithiadce, It also aflfords a beautiful illustration of the 

 almost imperceptible gradations by which Nature passes from 

 one system of form to another ; for in this genus, the aperture 

 being almost entire shews that it has still something in common 

 with that class of shells it is about to leave, and the evident rudi- 

 ments of a canal connect it with that class it is about to enter. 



The shell oiScalaria Clathratula^ (Turbo Clathratulus^Mont,} 

 appears very distinct from that of Scalaria Clathrus or S. commu' 

 nis, but the external organs of the animals inhabiting the three 

 species are alike ; the only difference consists in colour, which in 

 the S, Clathratulus is quite white, or pale yellowish white, whilst 

 in the two others, it is dark purple or black. 



Art. XXXV. On several Groups and Forms in Ornithology^ 

 not hitherto dejined. By William Swainson, Esq.^ 

 F.R.S., KL.S,, Sfc, 



[Concluded from p. 175.] 



Family Fringillida. ^ 



Sub-family Alaudina, 



^Rostrum forte^ subcylindricum^ immarginatum^ rectum^ naribus 

 plumulis setaceis obtectis ; rictu sub-barbato. Pedes subforfes ; 

 halluce forti, ungue recto. 



ALAUDA. 



Rostrum breve^ subconicum, 



Ala longed ; remigibus Imd^ 2ddy et Stidjere aqualibus^ longissimiSi 



Cauda sub'furcata. 



