Mr. W. L. Distant on Ilornoptera. 293 



the transverse section, which may possibly indicate the 

 dividing limit between the crown and the root, which I 

 suppose to })ave been imbedded in the jaw. There are very 

 faint transverse lines of growth beyond this ridge. 



If the ciown of the tooth were short, each lobe or bar of 

 the tooth might be expected to terminate in a cusp^ so that a 

 complex five-cusped reptilian tooth might originate from 

 folding extending through the root and crown, as in Mam- 

 malia like Edentates and Rodents. If the tooth is rightly 

 interpreted as a canine, then it might be followed by molar 

 teeth of similar complexity, and tend to show that the cuspi- 

 date character of certain mammalian and reptilian teeth may 

 not always be due to the mechanical influences of opposing 

 surfaces and varied movements of the jaws. 



There is no distinct layer of enamel beyond a surface-skin. 

 The calcigerous tubes of the dentine are always at right 

 angles to the external surface, remarkably dense, straight, 

 and parallel, always bending at the folds of the dentine as 

 they extend inward, so that the tubes tend to be approxi- 

 mately parallel. There is no appreciable difference from the 

 tube-structure in Dicynodon, though the tubes may be slightly 

 larger. The species may be known as P. pentangalatus. 



XLIY .—Bhynchotal Notes.— XXYl. By W. L. Distant. 



HOMOPTERA. 



Fam. Cicadidae. 



In revising the genera of this family, in preparation for a 

 projected complete synonymic Catalogue of the Cicadidae, I 

 propose to publish in advance descriptions of such new genera 

 and species as become necessary, and to give preliminary 

 synopses of the classification suggested. The synonymy is 

 somewhat extensive, and will be better deferred to the pages 

 of the Catalogue itself. 



Subfam. CicABiNjE. 

 Cicadince, Dist. Mon. Orient. Cicad. p. 3 (1889). 



Division POLYNEURARIA. 

 Lateral margins of the pronotum ampliated and more or 

 Ann. da Mag. N. Hist. Ser. 7. Vol. xiv. 20 



