362 



sions given by Ehrenberg for his largest specimens are: length, 

 7.35 mm.; width, 4.2 mm.; length of aperture, 5.7 mm. 



Bulinus cyrtonotus (Bourguignat). 

 Plate 18, figures 1-5. 



This species has been regarded as identical with Bulinus 

 tropicus (Krauss) by JickeH (1874) and Connolly (1912, Ann. 

 South Afr. Mus. 11, pt. 3, p. 248), and this synonymy was 

 adopted by Pilsbry and Bequaert (1927). Mr. P. L. Le Roux 

 has sent us a large lot of a Bulinus from the Aapies River near 

 Onderstepoort, Transvaal, which differ conspicuously from 

 tropicus, as shown by our figures 1 to 4- For a time we even 

 believed we had an undescribed species, until we happened to 

 see Bourguignat's figures of his Physa cyrtonota. A comparison 

 of these figures with our photographs will leave little doubt re- 

 garding the true identity of the Aapies River snails. It may be 

 noted that Aapies River is part of the upper drainage of the Oli- 

 fants River, whence B. cyrtonotus was originally described. 



Another lot of snails, which we likewise refer to B. cyrtonotus, 

 was found by Dr. Le Roux in a spring on a farm close to Bloemhof , 

 western Transvaal. Some of these specimens are unusually 

 large and have the aperture relatively longer. One of these is 

 shown in Plate 18, figure -5. 



The following description, based upon the series from the 

 Aapies River, may help to recognize the species. 



Shell. — Sinistral, large, widely umbilicate and deeply perforate, 

 turbinate, medium solid. Color light straw to white. Whorls 

 43^2 to 5, strongly convex; body whorl large and well rounded; 

 nuclear whorl milky white, smooth, flattened. Spire acute and 

 produced. Aperture evenly rounded, broadly ellipsoidal to sub- 

 circular, a little longer than wide, slightly flaring basally. Palatal 

 lip acute, parietal lip very short, limited only to a narrow area 

 of a rather thin callus on the body whorl; columella not twisted, 

 sHghtly folded over but not closing the umbihcal region, inclined 

 sHghtly toward the left and forming only a very slight angle with 

 the parietal lip. Sutures deeply impressed, occasionally shghtly 

 indented. Sculpture consisting of innumerable, very fine, axial 

 riblets (growth ridges) , irregularly spaced. 



