'252 



MR. G. C. ROBSON ON THE 



All the specimens examined showed a slender median tooth 

 with simple, rather piriform cusp. In z„ this is abnormal and 

 irregularly bicuspid. The admedian teeth have large heavily 

 conical mesocones, rather weak ectocones, and degenerate ento- 

 cones. In z the latter were very meagrely developed. The base 

 of the mesocones is very heavy, broad, and deep. Its inferior 

 edge is usually, but not always, turned upwards and outwards. 

 The adlaterals (e. g., about the fortieth) are bicuspid with low 

 stout mesocones and a very deep narrow basal plate. 



The pharynx. — The attachment of the pharyngeal muscles is 

 semilunar in shape. It will be more fully discussed under var. 

 fulgurata. There is an exceptionally short oesophagus passing 



Text-figure 2. 



Cochlitoma zebra var. obesa. 

 Salivary glands. 



into a crop measuring approximately 20 mm. +3. Interiorly 

 the latter exhibits a number of longitudinal folds with transverse 

 secondary connecting ridges, which form a rough trabecular 

 system. In both examples the crop is covered by the salivary 

 glands. The ducts of the latter originate in the usual position. 

 The glands themselves are in both cases asymmetrical, the left 

 being larger than the right. They are joined together in the 

 median line by two organic connections, one anterior, the other 

 posterior. Pilsbry (1919) mentions that the glands of Achatina 

 schiveinfurthii von Marts, are similarly joined, but only an- 

 teriorly. Between z x and z 3 are several considerable differences 

 in detail. 



