SUPPLEMENT.— HYATTIA. lv 



XV. Genus — Hyattia, 1 S. Buchnan. 



(Type: Hyattia pustulifera, sp. n.) 



Definition. — Platy-subpachygyral, subangustumbilicate ; subpauci- 

 septate, sublongi-angustilobate ; laterally subflexiradiate ; peripherally 

 anguliradiate, planifastigate, parvi-nonsepti-carinate. 



Distinction. — From Welschia, greater proportionate umbilication, 

 a more planifastigate periphery. 



Note. — The periphery is more definitely separated from the lateral pig. 12.— Radial 



, , . TTT 7 7 . line of Hi/attia 



area than in Welschia. pustulifera. 



1. Hyattia bullifera, 8. Buchm,an. Suppl., Plate XIV, figs. 1, 2. 



1886. Ammonites Mttbciiisonje obtusus, Quenstedt, Amm. Schwab. Jura, pi. 



lviii, fig. 10. 



Description. — Substeno-subpachygyral, latumbilicate, irregnlari-bullicostate. 



Note. — The description is taken from what is presumed to be a young shell, 

 and so the proportions would alter very much with age. 



The bullae rise prominently above the inner margin, and send forth two or 

 three costas. There are costae also between the bullae, so that of about five 

 costoa two are plain, and three are united into a bulla. 



Localities and Strata. — Gloucestershire, from the Pea Grit of the Cheltenham 

 neighbourhood, probably from Birdlip. Foreign : Normandy, Feuguerolles, 

 " Murchisonae bed " (M. L. Brasil). 



Date of Existence. — Murchisonae hemera. 



2. Hyattia pustulifera, 8. Buckman. Suppl., Plate XIII, figs. 1 — 3. 



Description. — Platy-subpachygyral, subangustumbilicate ; costate, in youth 

 irregulari-bullicostate. 



Distinction. — It is not the adult of bullifera, because the bullicosta^ are much 

 less pronounced. 



Locality and Stratum. — Dorset : Ohideock Quarry Hill, in the " Wild Bed." 



Date of Existence. — Murchisonae hemera. 



1 I11 compliment to Prof. Alpbeus Hyatt. 



