XXI.—On the Genus ICTIDOPSIS, 
by 
S. H. Haughton, B.A,, F.G.S., 
Assistant Director, South African Museum, Capetown. 
(Published by permission of the Trustees of the South African Museum). 
WO skulls belonging to this genus in the collection of the Durban 
Museum enable me to give a fuller account of the form than has 
hitherto appeared. The skulls are almost exactly similar. The larger 
one has been almost fully developed and shows most of the features. 
Two species of the genus Jctidopsis have been described, both very 
briefly :—Jctidopsis elegans from Harrismith, described by Broom 
(Proc. Zoo]. Soc. 1912, p. 872) and LZ. formosa, also from Harrismith, 
described by van Hoepen (Ann. Transvaal Mus. V, 3. Suppl. 2, 1916). 
The latter is said to be “larger than the type species, and its inter- 
orbital space is relatively broader. The hinder end of the nasal is only 
slightly broader than the front end.” Comparative measurements are 
as follows :— Durban Mus. 
I. elegans I. formosa specimen 
Greatest length ... ... 63mm, 8lmm. 72mm. 
Greatest width ... ... 42mm. 55mm. 44mm. 
Interorbital width wee) 2mm 18mm. 15°5mm. 
Six molars occupy a space of 13mm. 17mm. 16mm. 
This form comes, therefore, nearer to J. formosa than to J. elegans ; 
but it is possible that the differences between the two species may be 
due to individual variation. All the known specimens come from the 
Middle Beaufort Beds of Harrismith. The two skulls belonging to the 
Durban Museum, although obviously of the same species, show slight 
differences in size and relations due to crushing. 
The premaxilla carries four pointed incisors, which are bent back- 
wards. The fourth and smallest has a rounded anterior edge but is 
flattened posteriorly. The others are apparently nearly round in cross- 
section. 
The maxilla extends forward outside the premaxilla to the fourth 
incisor and forms the lower border of the foramen lying exterior to 
the nostril. It is highest above the canine and extends back below 
the orbit as a splint underlying the jugal. In addition to the canine 
it carries six molars. All the molars are cusped with a large pointed 
median cusp and a small anterior and posterior cusp, as in 
Nythosaurus. The first molar is small and the subsidiary cusps 
rudimentary. The 2nd, 3rd, and 4th are large teeth. The 5th and 
6th somewhat smaller ; but all have the cusps well marked. 
(243) 
