aOMPHOCEEATID^ . 
241 
Tetrameroceras Conradi, Barrande, sp. 
1847. Gomphoceras Conradi, Barrande, Haidinger, Bericlite liber die 
Mittlieil. von Freund, der Natiirwiss. in AVien, Band iii. p. 269. 
1867. Phragmoceras Conradi^ Barrande, Sjst. Sil. de la Bobeme, vol. ii. 
pt. i. p. 209, pi. xlix. 11. 1-11. 
Char. Shell sometimes straight, sometimes slightly curved. 
The transverse section is oval, the ratio of the two diameters being 
nearly as 9 : 7 at the last septum, and as 4 : 3 in the middle of the 
septate part of the shell ; the fossil is therefore more inflated at the 
upper part. The bodj’-chamber is of moderate size compared with 
the entire shell. The general surface of the aperture is nearly 
parallel with the plane of the last septum. The larger orifice is of 
Fig. 37. 
Outline of the aperture of T. Conradi, Barr. sp. (after Barrande, 
loc. cit. pi. xlix. f. 6). d, dorsal margin ; v, ventral. 
subtriangular form, the lobes being almost effaced, thus making the 
aperture larger proportionally than in any other species. The 
channel is very short and leads into the smaller orifice, which is of 
an oval form, and projects considerably from the ventral margin like 
a spout. The septa are moderately distant from each other, that is 
about -Jj- of the ventro-dorsal diameter. The siphuncle is placed at a 
little distance from the ventral border as seen at the last septum, but 
nearer the apex it is almost in contact with the test ; its elements are 
nummuloidal, and fiUed with radiating deposits. The surface of the 
test is ornamented with feebly-marked lines of growth which form a 
very distinct sinus on the ventral border of the shell, whilst they 
pass horizontally across the dorsal or convex side. Some specimens 
show traces of crenulations at the base of the cast of the body- 
chamber, and also slight longitudinal impressions connected with 
these. 
E 
