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



It is interesting to be able to redescribe this slug, as it lias 

 been a lost species, not recognized by subsequent authoi-s. 

 It is surely not an Ari'on, and it may represent a new genus, 

 unless it belongs to Morch's Oopelta, with which it seems to 

 agree externally so far as generic characters go. But until 

 the jaw and lingual dentition of A. aterrimus are known it 

 will be impossible to be certain of its proper position. 



Ariunculus Moreleti (Hesse) . 



Length 13 millim., breadth 2\ millim. Head dark brown. 

 Mantle dark brown, faintly mottled with black lateral bands, 

 bordered above by pale bands, and continuous with those on 

 body ; respiratory orifice a little anterior to middle. Body 

 pale grey at sides, with dark lateral bands and dark sub- 

 dorsal bands, four in all, leaving pale dorsal and subdorsal 

 narrow bands between them. Sole broad and grey. 



Described from a specimen kindly sent to me by Mr. J. H. 

 Ponsonby, collected at Tangier some years ago. It differs a 

 little from the original description, but is evidently the same 

 species. 



Pollonera has recently placed this species in Geomalacus^ 

 subg. Letourneuxia. 



Testacella alhida. 



1885. Testacella haliotidea, v. scutnlum (pars), Taylor and Roebuck, 

 Journ. of Conch, iv. April, p. 320. {Hab. Gibraltar.) 



1885. Testacella haliotidea, v. scutulum, siibv. albida, Cockerell, Sci. 

 Goss. October, p. 22b. {Hub. Gibraltar.) 



1887. Testacella, sp., Ponsonby, Journ. of Coucli. v. July, p. 195. {Hab. 

 Gibraltar.) 



1888. Testacella, probably haliotidea, Taylor, Journ. of Concb. v. July, 

 p. 340. {Hab. Gibraltar.) 



1888. Testacella, sp., Pollonera, Boll. Mus. Zool. An, Comp. Torino, 

 p. (3, figs. 10, 11. {Hab. Olot, Spain.) 



The dried type of T. alhida^ collected by the Rev. J. W. 

 Horsley at Gibraltar, is as follows : — 



Length 15^ millim.; sole 3 millim. broad; dorsal longi- 

 tudinal grooves about 2f millim. apart, oblique grooves well 

 marked. Sole separated from body by a groove and with 

 transverse grooves at intervals, well marked at sides. 

 Nucleus of the shell gone (broken or eroded). Shell pale 

 horn, growth-ridges strong. Length of shell 4 millim. 



The other white Testacella recorded from Spain (by Pollo- 

 nera) is placed here, although the Gibraltar shell is narrower 

 anteriorly than Pollonera's figure. It is not very likely that 



