Trochammine: of the Lower Malm of Aargau. 49 
there is usually no black at all at the base of these feathers, 
the outer tail-feather being entirely white. In some ex- 
amples, however, there isa little black at the base of this outer 
tail-feather ; and hence I can only look upon the Bornean 
bird as a race of the Indian one. It has heen named C. suavis 
by Dr. Sclater. 
Now the name Turdus macrurus of Gmelin (S. N.i. p. 820) 
is founded on the “ Long-tailed Thrush” of Latham (Gen. 
Syn. ii. part i. p. 72, pl. xxxix.), which is said to have come 
from the Island of Pulo-Condore, off the coast of Siam. The 
species from this island will doubtless prove to be the same as 
the Siamese and Burmese birds ; but, as figured and described 
by Latham, it agrees with C. swavis of Borneo. If, there- 
fore, it turns out to be specifically identical with the latter, 
the name of macrura must take precedence of Dr. Sclater’s 
name suavis. At all events, in the face of the uncertdinty 
that exists it seems better to speak of the ordinary Indian 
bird as Cittocincla tricolor (Vieill.), founded on Levaillant’s 
plate cxvui. in the ‘Oiseaux d’Afrique,’ where a very fair 
figure of the species is given; and considering that there is a 
bird in existence which has a white outer tail-feather, as figured 
by Latham, his ‘‘ Long-tailed Thrush” ought not to be referred, 
in any case, to the common Shémé of India and Burmah. 
IX.—WNotes on the Trochammine of the Lower Malm of 
the Canton Aargau (Switzerland). By Dr. Rupour 
Hauser, F.G.S. &c. 
[Plates HI. & IV.] 
THE zone of Ammonites transversarius (= Birmenstorfer 
Schichten=Etage Argovien I.) is represented in the Jura of 
the Canton Aargau by alternating layers of greyish more or 
less compact limestones and softer marls of the same colour, 
which overlie the ferruginous marls of the Upper Dogger 
(Callovian), and are covered by the clayey marls of the Middle 
Argovian étage (zone of Terebratula impressa). Their 
lithological character is nearly the same throughout the canton ; 
but their fauna and flora change considerably towards the 
upper limit; and though it is quite impossible to subdivide 
-this complex of strata into distinct subzones, yet, chiefly for 
microscopical researches, it is convenient to adopt three diffe- 
rent horizons, which in the course of this paper I shall call 
A, B, C. 
Ann. & Mag. N. Hist. Ser. 5. Vol. x. 4 
