xliv INFERIOR OOLITE AMMONITES. 



it will be seen that the present genus has a distinctly longer peripheral projection 

 — in other words, is more decidedly rostrate — than is Lioceras. The woodcuts, 

 figs. 3, 4, p. xxxiv, illustrate the difference in this respect between homoeomorphs 

 of the two genera. 



History. — Species of this genus, together with species of Lioceras, were 

 described as Lioceras opalinum in the body of the work, and consequently taken 

 as types of the genus Lioceras, p. 21. For remarks thereon see p. xxxiii. 



Geological Position. — The striate species of this genus occur in Dorset in the 

 top part of the Yeovil Sands, underneath the limestone with Tmetoceras ; and in 

 Gloucestershire in the hard ironshot limestone capping the Oephalopod-bed, — that 

 is in bed No. 15, sect, v, p. 43, and No. 4, sect, vi, p. 45, and underneath the sandy 

 ferruginous limestone. (See p. xxxv.) 



Remarks. — The genus, of which only a few species are known, presents certain 

 shells comparable to the striate and renovate series of Lioceras, which, however, 

 they preceded in point of time. So the species to be now described form part of 

 a series obviously parallel to Lioceras, but earlier in date. The likeness of Cypho- 

 lioceras to Lioceras has given much trouble in correlation of strata. 



1. Cypholioceras ? vitiosum, 8. Buchman. Suppl., Plate V, figs. 1, 2. 



Description. — Steno-subleptogyral, latumbilicate ; laterally flexicostate ; peri- 

 pherally angulistriate, subtabulate. 



Remarks. — The costae are connate near the edge of the inner margin, forming 

 a short, slightly stouter rib. Only fragments of the body-whorl of this species 

 have been found, and the pieces figured do not therefore belong to the same 

 specimen. 



The placing of this species in the genus Cypholioceras must be considered as 

 doubtful. It is a possible ancestor of plicatum, allowing that increase of the 

 peripheral projection of the radius accompanied increased compression. 



Locality and Stratum,. — Gloucestershire: Standish Beacon, in marl with 

 Terebratula haresfieldensis} 



Date of Existence. — Dumortierise hemera. 



1 It is the bed 19 of the section v (p. 44). In this bed the Ammonites are mostly fragmentary 

 and in poor condition. The Oramm. striatulum quoted is a mistake for Dumortieria (see p. 166). 



