clvi INFERIOR OOLITE AMMONITES. 



Falciradjate. 

 Nonsepticarina te. 



LXI. Genus — Hildoceeas, Hyatt 

 1889. Hildoceeas, This Monogr., p. 111. For radial line see PI. A, fig. 30. 



1. Hildoceeas semipolitum, 8. Bud- man. Plate XXII, figs. 30, 31 ; Plate A, fig. 28. 



1889. Hildoceeas bifeons, Tbis Monogr., PI. xxii, figs. 30, 31 ; PI. A, fig. 28. 

 1902. Hildoceeas semipolitum, Emend. Amm. Nom., p. 4. 



Remarks. — The characters of the species are the inclusion up to the lateral 

 sulcation, giving thereby a smooth central area; the numerous small costa?, the 

 compression of the whorl. 



Common low down in Cotteswold Sands {videHed 17, Section p. 45, as H.bifrons, 

 and footnote) of many localities of the Cotteswolds. In Upper Lias clay = 

 argillaceous condition of Cotteswold Sands at Overbury (Worcestershire). Not 

 yet found in that Upper Lias which lies below Cotteswold Sands, as at Stinch- 

 combe. 



Date of Existence. — Lilli hemera. 



Septicarinate. 



LXII. Genus — Vacekia, 1 , 8. Buckman. 



(Type : Vacekia Stephensi, sp. n.) 

 1899. Vacekia, This Monogr., Expl. of Suppl., PI. X. 

 Definition. — Subplaty-subleptogyral, sublatumbilicate ; subclensiseptate, sub- 

 longi-sublatilobate ; laterally anguliradiate ; peripherally peracutanguliradiate, 

 tabulate, subalti-septicarinate. (Radial line, fig. 156, p. clxvii.) 



Distinction. — The radial curve, with its extreme length of peripheral projection. 

 The only comparable genus from this point of view is Harpoceras, but that has 

 neither so long a peripheral projection nor so much lateral curvature of the radial 

 line. 



Remarks. — In his work, " Ueber die Fauna der Oolithe von Cap S. Vigilio " 

 (' Abh. der K. K. Geol. Reichsanstalt,' Bd. xii, No. 3, 1886), Vacek figures (pi. viii, 

 i'vj;*. 3, 0) certain specimens which appear to show a radial curve comparable with 

 that of the present genus. It is possible, therefore, that Vacekia would be their 

 correct genus, but they are not the same species as the one now under con- 

 sideration. 



1 In compliment to Dr. M. Vacek. 



