AND MOLLUSCA FROM ANGOLA, PORTUGUESE WEST AFRICA. 577 



Fam. Nerin^eid^. 

 Mrhilaia cf. nerinaeformis, Coquand. (PI. I, fig. 20.) 



Turritdla nerinaeformis, Coquand : Geologie et paleontologie de la region sud de la province de Constantine, 



1862, pi. iii, fig. 2, p. 176. 

 Mrhilaia nerineeformis, Pervinquiere : Etudes Paleont. Tunisienne : Gastropodes et Lamellibranches Crt'taces, 



1912, pi. iii, figs. 31-38, p. 39. 



Remarks. — This Gastropod is represented by a fragmentary limestone cast, 

 showing only the basal whorl and an imperfect aperture with obscure evidence of 

 a columella plication. The whorl has deeply excavated sides, besides bearing an 

 indication of marginal nodulations. Similar and better-preserved casts are among 

 the Angola fossils in the British Museum (Ansorge collection) ; they exhibit a wide 

 and deep sutural excavation, as well as occasional concentric bandings on the concave 

 walls of the volutions, which continue over the basal surface of the body whorl. 

 The existence, however, of the marginal nodulations, not referred to in the original 

 or later descriptions, creates a doubt as to the Angola specimens belonging really to 

 this species. They are, however, regarded as being closely related, and not to be 

 confused with the highly sculptured species Nerinsea capettoi which Choffat has 

 described and figured from the Dombe Grande area of Angola of a rather later 

 Cretaceous horizon.* 



Distribution. — The species belongs to the Cenomanian stage, and has been 

 recorded from Algeria, Tunisia, Dead Sea area, and Italy. W. Paulcke t has 

 recognised a similarly determined form in the Albian-Cenomian rocks of Peru. 



Occurrence. — In a cream-coloured limestone with mica and glauconite grains. 



Localities. — No. 294 — Plateau 800 feet E. of Lobito, associated with Ammonites 

 of the group S. inflata and other mollusca ; and Catumbella (British Museum 

 specimens). 



Fam. Hifponycid.e. 



Hipponyx sp. (PL I, fig. 21.) 



Remarks. — A specimen of Hipponyx, consisting of a limestone cast, must have 

 been originally about the size of an adult form of the well-known H. cornucopias 

 from the Eocene (Lutetian) formation of France. The proportions and contour 

 likewise show a considerable resemblance to the Tertiary species. It possesses 

 mostly a smooth surface, with, however, some obscure indications of the presence of 

 longitudinal striations, especially in the region of the basal margin, where they are 

 seen to be of thick and robust character. The fossil shows no concentric costee such 

 as are typical of Calyptrsea (?) corrugata of Forbes from the Upper Cretaceous rocks 

 (Ariyalur group) of India, J which, besides, is rounder and of smaller dimensions. 



* Mem. Soc. Phys. Hist. Nat. Geneve, 1888, vol. xxx, No. 2, pi. iii, figs. 15-18, p. 77. 

 t Neues Jahrb. Beilage — Band xvii, 1903, p. 275. 

 | Trans. Geol. Soc. London, 1846, ser. 2, vol. vii, pi. xii, fig. 11, p. 137. 

 TRANS. ROY. SOC. EDIN., VOL. LI, PART HI (NO. 15). 83 



