'296 Annals of tlie South African Muse inn. 



1904. Peroniceras (h-ariJicunt, Kossmat. Solger, " Foss. d. Mungo- 

 Kreide," Geol. v. Kamerun, II, p. 181, text-fig. 71, p. 182, and 72, 

 p. 183. 



A fragment (No. 4950), 72 mm. in length and belonging to a shell 

 just a little larger than the inner whorls of this species, refigured by 

 Kossmat, /. e., of about 85 mm. diameter, has a whorl-height and 

 thickness of 24 mm. It differs from the type of this species onlv in 

 having the inner tubercle nearer the umbilicus and more prominent, 

 /. e. projecting laterally and representing the region of greatest thick- 

 ness a character that would approach the present example more to 

 P. subtricarinatum. The suture-line, however, has 110 independent 

 second lateral saddle, like that of P. subtricarinatum, but, as in P. 

 ilravidicinn, this second lateral saddle forms only the internal branch 

 of the first lateral saddle, and there is a large umbilical lobe. The 

 principal lobe, though, is deeper in the specimen here described, and 

 the umbilical lobe shorter, than they are in Kossmat's figure. It may 

 also be added that the internal portion of the suture-line is very 

 variable ; the stem of the umbilical branch of the dorsal saddle mav 



/ 



be much broader than drawn, so that the details of the umbilical lobe 

 and the size of its lower internal and higher external branch may differ 

 considerably in consecutive suture-lines. No similar suture-line appears 

 to have been observed in any other species of Peroniceras, e. g. P. 

 pchneeblii, Boule, Lemoiue and Thevenin sp.,* which may be a related 

 form, occurring in Madagascar, does not show this type of umbilical 

 lobe, nor do the two examples of Peroniceras recorded by Crick f from 

 Zululaud. One of these, s/>. a (B.M., No. C18245), compared with 

 P. tridorsatum, Schliiter sp., resembles P. czurnigi, Redteubacher sp.,J 

 but not the "variety" figured by Grossouvre, and has a thinner 

 whorl-section than the present example. Since Crick only figured the 

 external half of the suture-line, the internal portion is here given for 

 comparison (PI. XXIII, fig. 2) . The other example, sp. ft (No. C18246) , 

 is much fatter, and in section and crescent- shaped costation resembles 

 P. rousseauxi, Grossouvre,|| but owing to the large size of these 

 specimens comparison with the small European types is difficult. 

 The tricarination is less distinct in this second specimen, and the 

 suture-line also is less well preserved, though very similar in the 

 character of the auxiliary lobes. 



* Loc. of. (ii, 1907), p. 37, fig. 20, pi. xii, figs. 2, 2 a. 

 t Loc. cit. (Third Report, 1907), pp. 226-7. 



* Loc. cit. (1873), p. 105, pi. xxiii, fig. 4. 

 Loc. cit. (1893), pi. xi, fig. 2. 



|| Ibid., pi. xi, fig. 5 a, b, p. 102. 



