Mr. T. D. A. Cockerell's Notes on Slugs. 99 



3. Mantle still more developed and more or less covering shell behind. 



a. American vii. Velifera, \V. G. Binn. ( V. Gabbi, W. 



G. Binn.) 



b. Asiatic viii. Austenia, sect. Cryptausteniee. (A. 



planospira, Bs.) 



B. Shell more or less whorled, but not truly Vitrinoid ; whorls subrudi- 

 mentary. 



1. Spiral -whorl complete below or not presenting the appearance of 



a smaller shell within a larger. Asiatic. 



a. Shell mostly exposed. 



a} . Shell well formed, ix. Austenia, Nev. (A. gigas, Bs.) 



a 2 . Shell horny x. Ibycus (Heyn.), G.-A. (I. fissidens, 



Heyn., I. sikimensis, G.-A.) 



6. Shell exposed only by an aperture in mantle, resembling that of 



Austenia xi. Ibgeus, sect. Cryptibyci. (J. magnificus, 



G.-A., sp.) 



2. Spire presenting the appearance of a small shell within a larger. 



a. Shell exposed only by an aperture in mantle. Australian. 



xii. Parmacochlea, E. A. Smith. (P. Fis- 

 eheri, Smith.) 



b. Shell mostly exposed. Asiatic. 



xiii. Africurion, sect. Pseudausteniae. (A. 

 ater, G.-A.) 



3. Shell external, mytiliform. African. 



xiii a. Estria, Poirier. (E. Alluaudi, Poir.) 



C. Shell slug-like, hardly or not at all whorled. 



1. Shell external, mytiliform. African. 



xiv. Aspidelus, Morelet. (A. Chaperi ,Morel.) 



2. Shell exposed by a hole in the mantle only or entirely covered. 



a. Shell horny, exposed by a rather large aperture. Asiatic. 



xv. Girasia, Gray. (G. Hooker i, Gray.) 



b. Shell oval, rudimentary, covered, animal like Girasia. Asiatic. 



xvi. Girasia, sect. Cryptogirasiae. (G. ru- 

 b-urn, G.-A.) 



c. Shell entirely concealed or exposed only by a very minute hole ; 



mantle with pale ridges ; dentition differing from Girasia. 



Asiatic xvii. Mariaella, Gray. (M. Dussumieri, 



Val. MS., Gray.) 



d. Shell exposed by a small aperture or none ; body more or less 



keeled. African. (Urocyclidse, Simroth.) 



d x . Mantle reticulate, perforate ; body without lateral ridgea. 



xviii. Uroct/clus, Gray. ( U. Kirkii, Gray.) 



(P. Mantle not reticulate, hardly or not perforate ; body without 

 lateral ridges ; penis-retractor muscles several. 



xix. Elisa, Heyn. (E. bella, Heyn.,= longi- 

 cauda, Fiseh.) 



7* 



