THERSITES. 129 



were perceived simultaneously and independently by Charles Hed- 

 ley and the writer. Our knowledge of the anatomy is due to 

 Hedley. 



The name Tliersites being anterior in date to Hadra, will replace 

 that term as a generic designation for the entire series. The same 

 name has been used in Crustacea and Insecta, but later than Pfeiff- 

 er's application of it to the present group. 

 T. richmondiana Pfr. vi, 90. Queensland, northern N. S. Wales. 



/. decolorata Pils. vi, 91. 

 T. novffihollandise Gray, vi, 91. New South Wales, Australia, 



depuyana Pfr. 



Section Glyptorhagada Pilsbry, 1890. 



Glyptorhagada PILS., Man. Conch, vi, p. 191 (Dec. 16, 1890). 



Depressed, keeled Badistes, having the surface corrugated by 

 strong oblique fold-like wrinkles, the outer lip hardly expanded ; 

 texture calcareous. Type H. silveri, pi. 27, fig. 19. (See also H. 

 kooringensis, pi. 27, figs. 7, 8, 9, 10). 



This is the South Australian expression of the Badistes type ; the 

 rudely sculptured, earthy shell responding to the arid condition 

 prevailing in the interior of South Australia, in accordance to the 

 well known law governing the modification of desert snails. The 

 anatomy is unknown. The species were formerly grouped in Rha- 

 gada, but their affinities are evidently with Badistes. 

 H. silveri Angas, vi, 191. H. bordaensis Ang., vi, 192. 



H. kooringensis Angas, vi, 191. H. howardi Aug., iv, 52. 



Section Badistes Gould, 1862. 



Badistes GLD., Otia Conch, p. 243, type H. gulosa Gld. PILS- 

 BRY, Man. Conch., vi, p. 94, 129. For anatomy see HEDLEY, Rec. 

 Austr. Mus., i, p. 196, pi. 29, 1891. 



Shell generally smaller and thinner than that of Sphcerospira, the 

 surface densely microscopically granulated all over ; often with a pe- 

 ripheral keel. Peristome a little thickened and very nairowly ex- 

 panded, suddenly dilated at the columellar insertion, closing or 

 almost closing the narrow umbilicus. Type T. gulosa, pi. 27, fig. 5 

 (see also pi. 27, fig. 3, T. bitceniata). 



The animal has a slight groove on each side, running from lips up- 

 ward and backward to mantle ; back with a median furrow banded by 

 two rugse or sets of rugae, on each side of which there are about six 



