SUPPLEMENT.— CYPHOLIOCERAS. xlv 



2. Cypholioceras? pigrum, 8. Buckman. Suppl., Plate V, figs. 3, 4. 



Description. — Subplaty-subleptogyral, sublatumbilicate; laterally flexicostate; 

 peripherally angulistriate, subtabulate. 



Remarks . — The costas are occasionally connate, as in the last species. 



The placing of this species in Cypholioceras is doubtful. It would not be the 

 link between vitiosum and plicatum, but would indicate an incipient departure in 

 another direction. 



Distinction. — From vitiosum, smaller umbilicus, less prominent costae. 



Locality and Stratum. — With the preceding species. Only fragments of body- 

 whorls have been obtained. 



Date of Existence. — Dumortierise hemera. 



3. Cypholioceras plicatum, 8. Buckman. Suppl., Plate VIII, figs. 7, 9. 



Description. — Platyleptogyral, costati-gradumbilicate, flexistriate. 



Note. — The portions of the whorls visible in the umbilicus show that the 

 species is costate in youth. 



Distinction. — The species is exactly comparable with Lioceras lineatum, and is 

 almost in the same stage of development. It is separable not only by the radial 

 curve, but by the difference of striation — the striae are coarse and much more 

 distant. 



Locality and Stratum. — Gloucestershire : Haresfield Hill, in the hard bed 

 below the sandy ferruginous beds. See above, p. xxxv. 



Date of Existence. — Opaliniformis hemera. 



4. Cypholioceras opaliniforme, S. Buckman. Plate XIII, figs. 1 — 3 ; Plate A, 



fig. 10 ; Suppl., Plate X, figs. 1—4. 



1888. Lioceras opalinum, This Mouogr., PI. xiii, tigs. 1—3; PI. a, fig. 10; 

 p. 3G, fig. 1. 



Description. — Platyleptogyral, concavi-excentrumbilicate, flexistriate. 



Distinction, — From plicatum, by umbilication and ornament, the strias being 

 much finer. It is exactly comparable with Lioceras opalinum; but besides the 

 difference of the radial curve, it may be noticed that the umbilicus is more concave 

 with sides less steeply sloped, and that the strias are not fasciated. 



History. — Figured and described in the body of the work with other platy- 

 leptogyral, angustumbilicate species, as Lioceras opalinum. A study of the radial 



