EASTERN PROVINCE SOUTHERN REGION SPECIES. 395 



Jaw tliiii, arcuate, ends but little attenuated; no median projection 

 to the cutting edge : anterior surface with numerous, sep- 



. ^ ' ■■■ Fig. 430. 



arated, delicate ribs, denticulating either margin, some- 

 times the upper median ones running obliquely towards 

 the median line, or even arranged en chevron, as in Macroce- 



' " ' Jaw ot 



ramus, with an upper median triangular compartment. ^' '*''"^'"''"*- 



The jaw of jB. dealhatus is here figured. It is quite arched. That of 

 B. Marielimis, Schiedeantts, and alternatus is of tbe same type. I have 

 given on Plate XVI, Fig. 12, of Proc. Phila. Acad. Nat. Sci., 1875, a 

 more enlarged view of one end of the jaw of B. sufflatus, to show more 

 accurately the character of the ribs (see also below, fig. 144). 



The lingual membrane of the genus as now received varies too much 

 to allow of a general description. It can only be said tbat the mar- 

 ginal teeth are quadrate, not aculeate. I have belqw described the 

 membrane of those of our species which I have examined. 



The general arrangement of the teeth on the membrane of B. deal- 

 hatus is as in Fatnla, the characters of the individual teeth being shown 

 in Terr. Moll., Plate X, Fig. E. There are 94 rows of 25-1-25 teeth 

 in one specimen examined. Another had 20-1-20 teeth, with 14 per- 

 feet laterals. The central tooth has a base of attachment longer than 

 wide, with but little expanded lower lateral angles, its lower margin 

 incurved, its upper margin broadly reflected. The reflection is large 

 and has subobsolete side cusps, bearing well-developed cutting points, 

 and a short, stout median cusp, bearing a short, stout cutting point, 

 not quite reaching the lower margin of the base of attachment. The 

 laterals are of the same general form as the centrals, but are larger, 

 bi'oader in proportion, and are rendered asymmetrical by the suppres- 

 sion of the lower inner angle of the base of attachment and inner side 

 cusp and cutting point. The marginal teeth are but a simple modifi- 

 cation of the laterals, formed by the proportionally greater develop- 

 ment of the reflection in comparison with that of the base of attach- 

 ment, and the greater development of the cutting points. On the 

 extreme marginals the cutting points are shorter and much blunter. 



The dentition of Bulimul us alternatus is figured on p. 203 of L. & Fr.« 

 W. Sb., I. (see also below, fig. 436). I have preserved no specimen from 

 which I can more accurately draw the individual teeth. It has 75 rows 

 of 37-1-37 teeth, all a[>pareutly of the same character as in B. dealhatus, 

 as is also the case in B. Schiedeanus. 



I have not examined B. Floridamis and B. patriareha. That of 



