xxx INFERIOR OOLITE AMMONITES. 



V. Genus — Phymatocebas, Hyatt. 



(Type: Phyhatoceras tirolense, Dumortier 1 sp.) 



1SG7. Phymatocera8, Hyatt, Bull. Mus. Comp. Zool., No. 5, p. 88. 

 Lillia, pars, auct. 



Definition. — Steno-subleptogyral, rursi-flexiradiate, tuberculate, septicarinate. 



History. — The species named by Hyatt as examples of bis genus have not been 

 figured, so the genus has never really had recognition. 



In answer to my queries the Professor writes to me, 2 " The Phymatoceras 

 robustum is the young of Am. tirolensis, Dum., Pt. iv, PI. xxiv," wherefore 

 that species becomes the type of the genus. 



Distinction. — The flexiradiate character sufficiently separates this genus from 

 either Lillia or Haugia, but mode of growth and manner of ornament also 

 distinguish the type species. 



Remarks. — The species now ranged under Phymatoceras (see p. xi) are placed 

 here from their possession of the flexiradiate character ; but more division is 

 obviously required on account of mode of growth and other characters. 



Some of the insert-group are perhaps non-tuberculate descendants of some of 

 the species arranged under Phymatoceras, and should therefore bear the generic 

 title of such species. 



1. Phymatoceras DcjMORTiERr, 8. Buckman. Plate XXIII, figs. 16, 17; Plate A, 



fig. 36. 



1889. Hauuia Ogerieni, This Monogr., PI. xxiii,figs. 16, 17 ; PI. A, fig. 36. 



1890. — Dumortieri, Ibid., p. 152, in correction. 



Description. — Platy-subpachygyral, angustumbilicate, flexicostate, parvituber- 

 culate, 3 subparvi-septicarinate. 



Remarks. — This species has the combination of small umbilicus, thick whorls, 

 and tubercles, characterising the Bayani-grovnp. But it cannot belong there, 

 because the periphery is not sulcate and the carina is hollow. 



1 This is not the same as the tirolensis, Hauer, and so the type of the present genus will require 

 a new name. 



2 June 1st, 1897. 



3 The tubercles are not so definite as shown in the figure. They are somewhat obscure, 

 elongate bulgings. 



