2 JO COCKERELL AND COLLINGE : CHECK-LIST OF SLUGS. 



4. Black, mouth not pale, sole olivaceous, unicolorous, 



length 46 mm. 



5. Black, mouth hardly pale, sole with central zone 



pale olivaceous, lateral zones black, and each 

 broader than central, length 37 mm. 

 So far as external characters go, specimens 1 and 2 

 should be nobrei, and 5 dasilne, while 3 and 4 seem some- 

 what intermediate. It is hard to believe they are not all 

 mutations of one species. 

 376 a-c. The grey forms of subfuscus may be distinguished as 

 follows : — 



1. Banded — (a) bands distinct, sole yellowish = citiereofuscus. 



sole whitish = typus. 

 (b) bands indistinct ... = krynickii. 



2. Hands wanting ... ... ... =griseus. 



" fasciis-obsoletis" {Conch., 1893, p. 115) is perhaps only 

 a descriptive term from a label written by Mr. Pollonera. 

 There is an unnamed form, found by Mr. Wilcock, which 

 is like citiereofuscus, but has an orange foot-fringe. 

 376 e.g. The reddish forms may be separated thus : 



1. Banded: 



(a.) reddish, bands black rufofuscus. 



(b.) yellowish, bands brown = mabillianus. 

 (c.) orange — aurantiacus. 



(d.) brick-red -rufescens. 



(e.) greyish red, bands blackish = ardosiarum. 



2. Bands wanting : 



(a.) yellowish, margin greyish —gaudefroyi. 



(/>.) yellowish, margin yellow succineus. 



(c.) brick-red, margin grey = lateritius. 



Of course these forms run into one another. The form 

 aurantiacus, as described by me, is bright orange, with the 

 bands ill-marked (Sci. Goss., 1886, p. 187). It may not 

 be the same as Locard's undescribed form, but in all 

 probability it is. The form vorntanni, Loens, 1S90, is 

 almost precisely the same thing, perhaps tending rather to 

 succineus. Var. audosiarum seems very close to Pollonera's 

 later described v. alpestris, but the latter is sometimes with 

 four bands. 



According to Pollonera, Avion olivaceus, Schmidt, is the 

 same as var. gaudefroyi. I have not had the opportunity 

 of consulting Schmidt's description, but if the names are 

 synonymous, olivaceus has many years priority. 



