8 
Annals of the Transvaal Museum 
saddle in the first lateral lobe. The external saddle and both lateral saddles 
are more or less symmetrically divided by a secondary lobe. The second 
lateral saddle lies partially on the umbilical edge. At a diameter of from 
31 — 39 mm. there are from five to six auxiliary saddles. The narrow dorsal 
lobe runs far backwards on the umbilical suture; it could not be made out 
whether it ends in a point or not. The dorsal saddle is narrow and like the 
lateral saddles divided by a secondary lobe. Its inner side is parallel to the 
Text-fig. 3. Gaudryceras varicos- 
tatum. Lobe-line of type up to 
the umbilical suture on a radius 
of 18 mm. About X3. 
Text-fig. 4. Gaudryceras varicostatum. 
Partial lobe-line of type from the first 
lateral lobe up to the dorsal lobe on a 
radius of 23 mm. x 3. 
axis of the antisiphonal lobe and its outer side runs from the bottom of the 
dorsal lobe forwards and inwards, therefore not parallel to its inner side. The 
antisiphonal lobe is very narrow and very long. The end, posterior to the 
posterior pair of transverse lobules, is very long and terminates in a point. 
The axes of the lobules, of which there are three pairs, stand practically at 
right angles to the axis of the lobe. The antisiphonal lobe is nearly as long as 
the dorsal lobe. 
Measurements : 
Diameter 
39-6 mm. 
(i-oo) 
Height of last whorl ... 
13-7 
( 0 - 35 ) 
Thickness of last whorl 
14-7 M 
( 0 - 37 ) 
Height of penultimate whorl . . . 
6-2 ,, 
(o-i6) 
Thickness of penultimate whorl 
8-2 „ 
(0-21) 
Diameter of umbilicus ... 
17*2 „ 
( 0 - 43 ) 
Most characteristic for the new form is its 
sculpture. 
The increase in size 
of the whorls is also peculiar. It differs from Gaudryceras Sacya Forbes sp. 
especially through its ornamentation; the shell of G. Sacya is covered with 
fine hair-ribs only. There is, however, a great resemblance between the two 
forms in the dimensions and the increase in size of the whorls. Gaudryceras 
varicostatum differs from G. multiplexum in the shape of the whorls and in the 
varied costation. It seems, however, that in younger whorls the ornamentation 
tends to approach that of G. multiplexum, although the longer coarse ribs on 
the end of the last whorl in our form are closer together than those of G. multi- 
plexum. The involution of the two forms is about the same. Gaudryceras 
varagurense Kossmat is more involute, while the flanks of its younger whorls 
are flattened. Its ornamentation is also different. Gaudryceras Kayei Forbes 
sp. has a different ornamentation, a different shape of whorl and a relatively 
wider umbilicus. Gaudryceras vertehratum Kossmat has a different shape of 
whorl. I do not see any difference with the specimen named Ammonites Kayei 
by Griesbach ( 5 , p. 63) and figured by Woods ( 17 , PI. XLI, figs. 8, 8 a). It 
cannot be made out with certainty, because the specimen has not been described. 
Griesbach only mentions a few old mouth-edges and flexuous ribs, which are 
