TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



Bornia Stoliczka, Cret. Pel. India, p. 266, 1871. Type B. corbuloidcs Phil., Fischer, 

 Man. de Conchyl., p. 1026, fig. 772 (wrongly named B. complanata, and copied from 

 Moll. Alg. of Deshayes, who called it Erycina Geoffroyi) , 1887. 



> Pythina Hinds, Zool. Voy. Sulphur, ii., p. 70, 1844. Type P. Deshayesiana Hinds, 

 op. cit., pi. xix., figs. 8, 9; Smith, Ann. Mag. N. Hist, for Sept., 1891, p. 327. 



Pythinia Deshayes, An. s. Vert, bassin de Paris, i., p. 694, 1858. 



Philippi's genus was heterogeneous, including species of Kellia and Lascra, 

 and was afterwards regarded by him as synonymous with Kellia, but when 

 the incongruous elements are eliminated there still remain several species which 

 are shown by their anatomical characters to be distinct from Kellia and for 

 which Stoliczka and Fischer have revived Philippi's name. 



Shell ovate or subtrigonal, subequilateral, with a more or less flattened 

 disk, the periostracum usually brilliant, the surface smooth or divaricately 

 more or less plicate ; an obsolete amphidetic external ligament present, a short, 

 slightly posterior, subumbonal internal resilium without a lithodesma, the 

 pallial line not sinuated, and the pallial area frequently punctate or radially 

 striate ; hinge with one moderately long posterior and two shorter anterior 

 laminje in the left valve, and in the right one anterior and one longer, some- 

 times remote, posterior lamina ; one or both the anterior laminae in either valve 

 may have the aspect of cardinals; hinge-plate usually excavated. 



Owing to the gradations which appear in the shells there are hardly suffi- 

 cient conchological reasons for separating the group into sections, but if this 

 be done Bornia must be retained for the smooth and Pythina for the divaricate 

 species. 



After long search, I finally obtained a specimen of Pythina Deshayesiana 

 from the Bishop Museum of Honolulu. It differs from the typical Bornia by 

 having the first anterior denticle in each valve strong, conical, and projecting; 

 there are two right and one left posterior lamins and a small, short, elevated 

 lamina in front of the conical tooth in the left valve only. 



It is of course possible that anatomical difi^erences may eventually be found 

 which may definitely separate Pythina and Bornia, but this remains to be de- 

 termined. One of the posterior laminae sometimes becomes duplex in well- 

 developed individuals of Bornia; conchologically the flattened disk and shorter, 

 more central resilium enable one to separate the species from the nearly related 

 but more globose Kellias. The reniform outline of many of the species may 

 be due to commensalism. Ceratobornia (see p. 1152) has anatomical pecu- 

 liarities. 



Bornia is represented in the Chickasawan or Lignitic Eocene of the United 



