loO FKOCEEDIXGS OF THE MALACOLOGICAL SOCIETY. 



Jlfrco^Iossa Cassiniaua, R. B. Xewtou. — Svst. List Ed-wards Coll. 

 British Museum. 1891, p. 291. 



Shell compressed, with tlatteued sides ; periphery narrowly rounded ; 

 nmbilicus closed; siphunolo near the dorsal margin. It somewhat 

 resembles H. Danicus from the Upper Chalk, but may be readily 

 distinguished by the position of its siphuncle, which in the Cretaceous 

 species is nearly central, and by its more compressed whorls. The 

 present species, although not quite a typical Hercofflossa, by reason of 

 the absence of the tongue-shapeil lobes, may be provisionally retained 

 in that genus. The tj'pe specimen ligured by Messrs. Foord and 

 Crick being in such a fragmentary condition, we have deemed it 

 advisable to figure the only other specimen in the British Museum 

 (Xatni'al History) fi'om Sheppey, which is in a much better state 

 of presei-vation. This exhibits very clearly the deep sinuous septa, 

 as well as the structure of the exterior of the shell; the umbilicus 

 is uncovered on the right-hand side. The opposite side, including 

 the umbilical region, is much hidden by fragments of the outer 

 portions of the shell, which are crushed into it. It is imfor- 

 tunately not complete, several of the later septa being missing. 

 The outer portion of the shell is covered with slightly sinuous, 

 closely set, striie ; whilst some obsciire lines, running spirally, 

 cross these obliquely, producing reticulation in places. The specimen 

 now figured is more tumid than the type, but we do not think there 

 is sufficient evidence to warrant us in creating a new species. In 

 some respects IT. Cassiniana resembles the species of the genus 

 Cimomia, Conrad.^ but on reference to the figures of the type, Xaufilm 

 Burtini, Galeotti,- it will be seen that the sinuosity of the septa is 

 much more pronounced in onr shell than in the Belgian species 

 referred to. The deep sinus observable in certain Xautili, and 

 directed posteriorly on the dorsal portion of the septa, where the latter 

 wrap round the preceding whorl, is well exemplified in H. Cassiniana 

 by a deep longitudinal slit. Greatest diameter 50 mm. ; width across 

 the umbilical region 30 mm. Very rare, two specimens known. 



Formation. — London Clay. Localities. — Pinchley (type) and Sheppey 

 (Figs. 4, 5). 



Genus ATUEIA, H. G. Bronn. 

 Lethaea Geognostica, 1838, voL ii. pi. xlii. fig. 17, pp. 1122, 1123. 



Type. — Xautilus Atari, Basterot ( = Xautilite de Dax, Montfort). 

 Montfort. — Bufiton's Hist. Xat., edited by Sonnini, 1802, Mollusques, 

 vol. iv. pp. 240, 252, pi. xlvi. fig. 1. Basterot. — Mem. Soc. Hist. 

 Is'at. Paris, 1825, vol. ii. part 1, p. 17. 



Shell compressed, involute, not umbilicated. Septa numerous, with 

 an angular lobe on each side, directed posteriorly, and abutting against 



' American Journal Conch. 1S66, vol. ii. p. 102. 



^ Burtin, Oryctog. Bruxelles, 1784, pi. liv. ; Galeotti, Mem. Cour. (4to.), 1837, 

 Tol. xii. p. 140. 



