The Cretaceous Fauna of Pondoland. 323 



separated by shallow interspaces. Growth-ridges cross the spiral 

 ribs. 



Aperture very large, more or less oval, but angular anteriorly and 

 posteriorly and at the carina. Posterior canal well developed, but 

 short. Anterior canal rather short in old specimens, of moderate 

 length in younger examples, slightly curved outwards. Outer lip 

 smooth ; thin, except posteriorly. Inner lip large, becoming very 

 thick and expanded in old individuals. 



Affinities.— P. africana resembles the examples of i?ajja can- 

 cellata (Sowerby) figured by Stoliczka" from the Trichinopoli 

 Group, but possesses more numerous and closer spiral ribs, a 

 better developed posterior canal, and, in most cases, a shorter 

 spire. Examples from the Upper Turonian and Lower Senonian 

 of Europe have been identified with Raioa canceUata by Geinitz, 

 Fritsch, Sturm, Deninger, &c. 



In its well-developed posterior canal, and in the prominent ridge 

 behind it, P. africana is similar to the larger example of P. Hom- 

 hroniana (d'Orbigny) figured by Wilckenst from Quiriquina, but it 

 differs in the character of its ornamentation. 



An imperfect specimen from Umkwelane Hill (Zululand), figured 

 by Etheridge,:J: may perhaps be related to P. africana. 



Bemarks. — There are three examples of Pyropsis africana, which, 

 with the exception of the anterior canal, are well preserved. 

 When perfect the canal may have been fairly long, but was 

 evidently relatively longer in young than in old individuals. The 

 posterior canal and the prominent ridge behind it appear to develop 

 chiefly in old individuals, so that the resemblance to Rapa canceUata 

 is greater in young than in old specimens. The genu.s Piiropsis is 

 included by Zittel and by Cossmannj in Tiulicnla, to which it is 

 certainly closely related. 



P. Braircli, Meek and Hayden, is found in the Pox Hills Group of 

 Missouri, and P. coloradoensis, Stanton, occurs in the Pugnellus 

 Sandstone of the Colorado Formation of Colorado. 



* Cret. Fauna S. India, vol. ii. (18G7), p. 154, pi. xii., figs. 12-16, pi. xiii., 

 figs. 1-4. 



t Neues .Jahib. Mr Min., &c. Beil.-Band xviii. (1904), p. 213, pi. xviii., fig. 8. 

 Also d'Orbigny, Voy. Pole Sud., *c. (1847), pi. iv., fig. 31. 



\ Second Rep. Geol. Surv. Natal and Zululand (1904), p. 85, pi. iii., 

 figs. 10, 11. 



§ Paleoconch. Comparee, iv. (1901), p. 68. 



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