xxii INFERIOR OOLITE AMMONITES. 



Locality and Stratum. — Gloucestershire : Coaley "Wood, in the Cotteswold Sands 

 (Bed 16 of section vi, p. 45). 



Date of Existence. — Variabilis hemera. 



IV. Genus — Haugia, S. Buclcman. 



(Type : Haugia variabilis, d'Orbigny sp.) 

 18S8. Haugia. This Monogr., p. 45, 18S9, p. 142. 



Definition. — Subplatyleptogyral, sublatumbilicate, subcrassornate, versi-recti- 

 radiate, alti-septicarinate, subdensiseptate, suborn ati-lobate. 



Remarks. — The species placed under Haugia are really capable of further 

 division. The arrangement is confessedly somewhat arbitrary. 



Distinction. — In general Haugia is less strongly ornate than Denchnannia, but 

 rather more ornate than Lillia. It is more carinate than either. 



The comparison of Haugia. and Lillia is difficult because the species referred 

 to the genera are not in the same degree of phyletic development. But Bayle's 

 pi. Ixxxii shows in figures of Lillia Lilli and " Hammatoceras Ogerieni" some of 

 the differences which may be expected between the species of the two genera. 



a. The n avis-group. 



The greater proportionate compression in conjunction with similar umbilica- 

 tion, and the greater develojnnent of the carina, distinguish this group from 

 Denchnannia. The ornamentation of Denckm. torquata, much coarser than that 

 of adult H. navis, the carina less developed, and the L. broad instead of 

 narrow, show that that species cannot belong here. 



1. Haugia navis (Dumortier). Suppl., Plate II, figs. 5 — 7. 

 1874. Ammonites navis, Bum., PI. xx, figs. 3—5. 



Description. — Subplatyleptogyral, sublatumbilicate, subcrassornate, subrursi- 

 recticostate, alti-septicarinate, subdensiseptate, L. narrow. 



Distinction. — This species is distinguished from variabilis chiefly by coarser, 

 more irregular ornamentation. It also seems to be more quickly coiled and rather 

 thicker. 



Locality and Stratum. — Somerset : Barrington, near Ilminster, " Upper Lias," 

 above Hildoceras bifrons. 



Date of Existence. — Variabilis hemera. 



