10 
Annals of the Transvaal Museum 
lobe-line. Gaudryceras leptonema Sharpe sp. (2, p. 32, PI. XIV, fig. 3) differs 
in shape and number of whorls. Gaudryceras Rouvillei de Gross. (10, p. 228, 
PI. XXXVII, figs. 7, 10) shows differences in the lobe-line. Comparison with 
the Japanese species of Gaudryceras is difficult, because our specimens are very- 
small, while the Japanese species are mostly known by large specimens. It 
seems, however, that our form has a number of whorls at a given diameter, 
which exceeds that of some Japanese species. It differs from nearly all of 
them through its fairly large umbilicus and its rapid increase in size. Another 
question to be dealt with is, whether the present specimens are or are not 
young stages of known Pondoland forms. Gaudryceras amapondense v. Hoepen 
( 20 , p. 143, PI. XXIV, figs. 4, 5) is the only species which warrants the question. 
Its young stage, however, shows a large umbilicus and slowly increasing whorls. 
The dimensions show different relations. 
Two specimens of this species have been found. Named after the former 
Pondoland chief Sigcau. 
Genus TETRAGONITES Kossmat, 
Tetragonites superstes n.sp. PI. II, figs. 17 — 20, text-fig. 6. 
Shell discoidal, umbilicated, consisting of a few thick whorls. Whorls 
broader than high. Greatest thickness at, or slightly internal to the middle 
of the flanks. Sides of whorl and external surface slightly convex. The shell is 
strongly convex between the external surface and the flanks. Umbilical surface 
vertical to the plane of symmetry and of moderate height. There is no sharp 
line of demarcation between the umbilical surface and the flank, but the two 
surfaces pass very abruptly into each other. Involution two-thirds. 
The ornamentation of the shell is very delicate. The external surface and 
the greater part of the flanks are apparently smooth both in the type and in 
the paratypes. However, large portions of the shell are lost in the type and it 
is not impossible that extremely fine growth-lines have been worn away on 
the parts most exposed. The shell of the paratypes is well preserved. The 
umbilical surface and the internal part of the flanks is covered in two specimens 
by very fine, closely set growth ridges, which are only visible with a magnifying 
glass and which have the same course as the mouth-edges. Further the shell 
is ornamented with some, apparently five, spiral ridges. These ridges are only 
visible on most of the last whorl of the type and on the last quarter of the last 
whorl of another specimen and on half the last whorl of a third specimen, the 
smallest of the three. They are very low, in fact only -just distinguishable. One 
of these ridges follows the medial line of the external surface. Two others are 
on each side of the shell on the very convex surface between the external 
surface and the flanks. The type is complete up to its last apertural edge. The 
umbilical portion of this edge stands practically vertical on the umbilical 
suture. On nearing the edge of the umbilicus it leans slightly forwards and, 
on passing over the edge it is directed strongly forwards, to such an extent as 
to nearly form a tangent to the spiral of the umbilical edge. On the flanks the 
mouth-edge is quite straight. On the junction between external surface and 
flanks the edge turns, so as to pass transversely over the external surface. The 
edge is slightly concave forwards on the middle of the external surface. The 
mouth-edges are represented by grooves on the cast. On the shell they are 
visible as very slight ridges ; these ridges are so slight, that they can easily be 
overlooked. I can only And two old mouth-edges in the type; these are on the 
living chamber and fairly close together. On another specimen, of which a 
portion of the living-chamber is preserved, four old mouth-edges are clearly 
