Reference List of South African Non-marine Mollusca. 247 



Type in Zurich Museum. 



Hab. OVAMPOLAND. Ondonga (Schinz). 



DAMABALAND. Okosongoho (Hermann). 



BECHUANALAND. Lake Ngarni ; Garu ; fossil, south of Hardeko 

 Drift, Botletle Eiver (Passarge). 



BRITISH BECHUANALAND. Witkop (subfossil, Schultze). 



?CAPE OF GOOD HOPE. Port Elizabeth (fide Morelet). 



Considered by Bottger to be very near diaphana ; Mousson's 

 figure, however, closely resembles angolensis, which is known from 

 Angola and Daruaraland. 



523. ISIDOEA SERICINA, Jickeli. [S.A.M.] 



1874 Isidora sericina, Jick., Fauna N.-O.-Afr. p. 194. pi. 3, f. 2. pi. 7, 



f. 11. D.E.F. 

 1886 Physa Cless., Conch. Cab. p. 325. pi. 39 (1884), 



f. 12. D.F. 

 1898 M. & P., Proc. Mai. Soc. iii. p. 182. L. 



schackoi 



1908 Isidora sericina Neuville & Anthony, Ann. Sci. nat. 

 Paris, viii. pp. 274, 275. N.F. 



Type in Zool. Mus. Berlin. 



Hab. " SOUTH AFRICA" (in coll. Ponsonby). 



CAPE OF GOOD HOPE. Forty-eight miles from Port Elizabeth 

 (" schackoi," in coll. Ponsonby). 



Described from Abyssinia. 



Careful examination of the two large series, on which the record 

 of sericina and schackoi from South Africa was originally based, 

 proves them to contain only one species. Professor Thiele has 

 kindly compared this with Jickeli's types, and informs me that it is 

 distinct from schackoi, but nearly allied to sericina, with which it 

 may be identical. I have therefore removed schackoi from the South 

 African list. Neuville and Anthony place sericina in the synonymy 

 of contorta, Mich. The shells are certainly very similar, and might 

 merge into one another, but Jickeli differentiated the two species by 

 their radula, and, under these circumstances, it may be inadvisable 

 to unite them without more extended investigation. 



524. ISIDORA TROPICA (Krauss). [S.A.M.] 



1848 Physa tropica, Krs., Sudafr. Moll. p. 84. pi. 5, f. 12. D.F. 

 1856 ,, Bgt., Eev. et Mag. Zool. viii. p. 236. D. 



,, ,, Amen, malac. i. p. 175. D. 



