TEOCHOCERATID^. 
35 
well marked on tlie sides and back of the shell, but becoming almost 
obsolete upon the concave side of the body-chamber. The annula- 
tions form a deep backward pointed sinus upon the convex border 
of the shell ; they are as distinctly seen upon the cast as upon the 
test, but become obsolete close to the aperture in adult examples. 
The annulations are 5 lines apart where the shell has a diameter of 
1|- inches. The surface of the test is ornamented with fine, slightly 
waved, and regular longitudinal striae, which pass over the annula- 
tions ; there are about 5 of these striations in the space of 1 line. 
A slight raised line or keel along the median line of the convex 
border is visible upon the cast in some examples. Epidermids are 
also seen upon the cast. 
Remarks. This species is distinguished from all others of the same 
group by its size, by the position of the siphuncle, and by the absence 
of fine transverse lines upon the test. 
Horizon. Etage E ( = Salopian). 
Locality. Kosofz, Lochkow, Bohemia. 
Fairly well represented in the Collection. 
Trochoceras trochoides, Barrande. 
18G7. Trochoceras trochoides, Barrande, Syst. Sil. de la Boheine, vol. ii 
pt. i. p. 116, pi. xxix. ff. 16-26. 
Sj}. Char. The number of whorls in this species scarcely amounts 
to two; its asymmetr}’ is very distinct, tho inner whorl being 
elevated above the plane of the outer. The transverse section is 
nearly circular, though the transverse is to the ventro-dorsal axis as 
10 : 9. The shell increases its diameter about three times in the 
last volution. The body-chamber is in contact with the other 
whorls, except for a very short distance near the aperture. The 
latter is slightly sinuated on tho convex border. The greatest 
distance of the septa from each other as measured on the sides of the 
shell, in the median line, is 2 lines, which equals about h of the 
ventro-dorsal diameter. Tbe siphuncle is midway between the 
centre and the convex border ; its elements are cylindrical. The 
surface of the shell is ornamented with very prominent oblique an- 
nulations, which are as strongly marked upon the cast as upon the 
test. They form a deep sinus upon the convex border. The test is 
covered with a beautiful network of prominent raised lines, forming 
rectangular meshes. The longitudinal lines are a little stronger, 
and much less numerous than the transverse ones which they cross. 
The former are exactly 1 line apart, near the aperture, while it 
would require at least four of the latter to fill that space. 
1)2 
