466 Mr. P. L. Sclater on new Birds from South America, 



We have unfortunately only a single specimen of this species 

 in the British Museum, which was sent from the Ohio by 

 Mr. Anthony. This example only differs from the specimens 

 found by Mr. Rowse in the front side being rather attenuated 

 and produced, while in the British specimens this part of the 

 shell is regularly rounded ; but I have no means of ascertaining 

 whether this is the usual state of the species, or only an acci- 

 dental variation in the individual we possess, and one can scarcely 

 believe, without better proof, that the same species should be 

 found in Europe and the United States ; therefore I shall for the 

 present consider it as distinct. 



The species is intermediate in size and form between Sphcerium 

 rivicola and >S^. corneum, 



Sphcerium pallidum. 



Shell oblong, pale whitish yellow on the circumference, 

 slightly .concentrically striated, rounded before, 

 rounded and rather truncated behind ; sides rather 

 swollen, evenly convex ; the cardinal edge rather 

 produced, nearly straight, and slightly compressed 

 on each side the umbo ; the umbo regularly convex, S. pallidum. 

 rather in front of the middle of the shell, sometimes slightly 

 crumpled. 



The foot very large ; the siphons elongate, united nearly to 

 the tip ; the apices conical, the upper the smallest. 



The young are compressed, rather rounded, gradually be- 

 coming more gibbous and elongated as they increase in size. 



Inhabits Grand Junction Canal near Kensal Green. 



The largest specimens are |^| of an inch long, ~\ high, and 

 /^ thick. The average-sized specimens are ^ inch long, \ thick, 

 and 2^ high. 



The living specimens emitted when in confinement several 

 young shells about 1 line long. 



May 20, 1856. 



XLIII. — Descriptions of eight new species of Birds from South 

 America. By Philip Lutley Sclater, M.A., F.Z.S. &c. 



1. Synallaxis castanea. 



S. brunnescenti-castanea unicolor : plaga magna gutturali nigra : 

 loris obscuris : mento fulvescenti-albido : remigibus intus ni- 

 gricantibus : cauda unicolore castanea longissima ; rectricibus 

 tantum octo et harum una utrinque extima brevissima. 



Long, tota 5*5 ; alse 2'3; caudse 4*1 poll. Angl. 



Hab. in vie. urbis Caraccas in Venezuela. — Mus. Brit., Paris. 



There are several specimens of this fine Synallaxis in the Bri- 



