278 Annals of the South African Museum. 



The smaller example is distinguished from equal-sized European 

 specimens of the subcristatus type, as figured by d'Orbigny and 

 Sowerby (in Fitton), in having straighter and more rigid costation. 

 This is reminiscent of D. cornut'tan, and some fine specimens of the 

 latter species, much larger than Pictet's type, from the Astier Collec- 

 tion in the British Museum (e.g. Nos. 37610 [88]) show comparable 

 ornamentation near the end, after decline of the tuberculatioii has set 

 in. Only the thickness is far greater in Pictet's species than in 

 D. cristat'itm, and the prominences on the inner whorls are blunter. 



The Schloenbachia sp., recorded by Crick* from the Middle Tributary 

 of the Manuan Creek, and compared with d'Orbigny's A. delarnei and 

 Pictet's A. cornutus, is a badly preserved and immature example of a 

 Dipoloceras ; but a larger fragment (No. C18301) of a similar form, 

 close to both the large D. cornuhim from Escragnolles, mentioned 

 above, and to the typical D. cristatiim in Brongniart, was worked out 

 of the matrix of one of the Nautili described on p. 244 bv Mr. Crick 



*. 



but was not referred to in the paper. 



The large example, in peripheral view of the final, costate portion, 

 somewhat resembles Marcou's A. sltumardi-f ; but that species has 

 no "flares," has weak outer and strong inner tubercles, and is tran- 

 sitional from Dipoloceras to Subschloettbachia. 



Locality. Manuan Creek. Coll. Eesident Magistrate, Ubombo. 



5. DIPOLOCERAS QUADRATUM, sp. nov. 

 (PI. XXV, figs. 3 fl-c.) 



Cf. 1847. A. bouchardianws (d'Orbiguy) Pictet, In Pictet & Koux, 

 Moll. Foss. GITS. Verts., p. 350, pi. viii, fig. 9. 



This species is based on a specimen (No. 4955) of the following 

 dimensions : 



Diameter . . . .43 mm. 



Height of last whorl . . 40 per cent, of the diameter. 



Thickness . . ? 45 







Umbilicus .... 30 



Like the closely comparable specimen figured by Pictet, this 



* Loc. cit. (1907), p. 247, B.M., No. C1S308. 



t ' Geology of N. America' (1858), p. 33, pi. i, %. 1 (misspelt schumardi on 

 plate), holotype in B.M. (Geol. Soc. Coll.) No. 12662. The geological position 

 of this form, in the Upper Duck Creek Formation, below the Fort Worth Beds 

 with Subsckloenbachia leonensis, seems to correspond with that of the European 

 Dipoloceras cristatinn. 



