OF CONCHOLOOY. 



14^^ 



Fig. 20. 



,Fig. 20. Platidia anomioides, haemal valve with animal, 'y". 

 Fig. 21. Same, /, pedicel notch; c, apophyses; o, ovaries. 



Type. Platidia anomioides, Scacchi, sp., fig. 20, 21. 



Terehratula anomioides, Scacchi, Phil. Moll. Sicil. ii, p. 69, 

 pi. xviii, fig. 9 (1844). 



This species is equal to appressa, Forbes, + seminulum, Dav. 

 (not T. seminulum, Phil.), and possibly -(- eusticta, Phil. (?) 



Ilab. Mediterranean, living, 95 fathoms, and fossil (ensticta) 

 in the pliocene of Palermo. 



If the last mentioned species is really synonymous with P. 

 anomioides, as some authors have suggested, the former name 

 will have to take precedence, as it was published in 1886. 



The other recent species of Platidia are : 



Platidia lunifera, Phil., 1836, Moll. Sicil. i, p. 97, pU vi, fig. 



16. 

 Platidia Davidsoni, Deslongchamps, An. Nat. Hist. 1855, 



xvi, p. 443, pi. X, fig. 20, a, b, c, d. 

 Both of the above species are found in the Mediterranean. 

 ? Platidia gigantea, Desh., Maillard, Moll. Isl. Bourbon, 1864. 

 Hah. Isle de Bourbon, S. Ocean. 



Section MEGATHYRIN^. 

 Ar^iopidce, King, Perm. Foss. p. 142. 



Shell with a straight, wide hinge-line ; apophyses consisting 

 of a submarginal loop, attached at the hinge margin and provided 

 with crura, intersected by one or more submarginal elevations or 

 septa. 



Brachia submarginal, surrounding a smooth disk or membrane, 

 in the middle of which the mouth is situated. Pedunculated. 



