346 PROF. W. AHALITSKT. ON PEKMIATT [Aug. 1 895, 



likeness to the cast of Palceomutela Icevis from the Russian Permian, 

 though without more material it would be somewhat premature to 

 identify it with the Russian forms. 



Dimensions: length 4-5, breadth 2-2| ; Russian forms: length 

 9, breadth 5. 



Tn Russia Palceomutela Icevis is found on the upper horizon of the 

 Permian marls and sandstones of the Oka-Volga basin, near 

 Gorbatoff. 



Locality. South Africa : Graaf Reinet. 



Pal^omtjtela, sp. n. (PI. XIII. fig. 4.) 



Shell small, ovately oblong, convex, smooth ; umbones prominent, 

 mesial obtuse, directed slightly forwards. The dorsal margin 

 slightly curved, anterior margin rounded, posterior margin sloping 

 somewhat obliquely backwards. The lower border is nearly 

 straight. All angles are rounded. The surface has fine irregular 

 concentric striations. I think that this form is perhaps a young 

 specimen of the group P. Keyserlingi. I cannot define it exactly, 

 because sometimes the young forms of Palceomutela are very 

 different from the adult stage. It is possible that this form will 

 subsequently prove to be a young specimen of P. trigonalis. 



Dimensions : length 7, breadth 5, depth 4. 



Locality. South Africa : Diamond mines at Kimberley. 



Paljsanolonta, n. g. 



1852. Anodonta, Forbes, Mem. Geol. Surv. Irel. Expl. Sh. 147 and 157, p. 16 

 {A. Jukesii). 



1859-1863. Anodonta, Ludwig, Palseontographica, vols, viii., ix., xi. 



1861. Anodonta, Geinitz, ' Dyas.' 



1868-1878. Naiadites, Dawson, pars, ' Acadian Geology,' 2nd and 3rd eds. pp. 204- 

 205. 1 



1892. Naiadites, Amalitsky, Palseontographica, vol. xxxix. 



1894. Naiadites, Netshayeff, 'Die Fauna der permischen Ablagerungen des 

 ostlichen Theils des europaischen Russlands.' 



1894. Carbonicola, Wheelton Hind (pars : only edentulous forms), Palseont. Soc. 

 vol. xlvi. 



Diagnosis. Shell equivalve, inequilateral, elongated or oval, 

 nnioniform, smooth. Ligament external, situated behind the 

 umbones. Hinge-margin toothless, curved, angulated or straight, 

 sometimes thickened. The scars of the adductors are strong, oval, 

 or elongated ; the small scar of the pedal muscle is separated from 

 the anterior adductor and situated under the hinge-line ; very 

 rarely a supplementary small lunate scar is situated behind the 

 anterior scar of the adductor. Pallial scar entire. Valves closed. 



The type is Palceanodonta Castor, Eichw., sp. Por synonymy, etc., 

 see my paper, ' Ueber die Anthracosien der Permformation Russ- 

 lands,' Palaeontographica, vol. xxxix. (1892) p. 192, pi. xxii. figs. 

 40-43. 



1 A discussion of the synonymy of Naiadites, Dawson, which is contained in 

 Dr. Wheelton Hind's papers, Quart. Journ. Geol. Soc. vol. xlix. (1893) and 

 vol. 1. (1894), will be published in a subsequent memoir. 



