34 



THE CONCHOLOGIST. 



mantle enclosing respiratory orifice ; foot- 

 fringe ^Yithout lineoles ; body and mantle 

 minutely speckled with pale yellow ; 

 tentacles, blue-grey. 



This is simply a variety of hortensis, 

 with colourless slime. The yellow sole 

 has been thought one of the most in- 

 variable specific characters of A. hor- 

 teuiis, l)ut in this slug it is lost, and 

 \et the affinities of the animal are so 

 obvious that it would be absurtl to 

 make a new species of it. 



Other forms of A. hortensis which deserve 

 further enquiry are recorded in the following 

 places:— (i) "Science Gossip," 1884, p. 236. 

 (2) "Nat. World," 1885, p. 222. (3) " Journ. 

 of Conch.," 1887, p. 181. {4) "Journ. of 

 Conch.," 1891, pp. 349-352. (5) "Journ. of 

 Conch.," 1883, p. 40, &c. 



I have not dissected many specimens, and 

 have little to say about the anatomy from 

 personal observation. There seems to be 

 a considerable variability in the form of the 

 penis-sac. The xA.cton A. hortensis has that 

 organ straight, or but little curved ; while 

 in an example found at Chislehurst, Kent, 

 in July, 1885, it was sharply bent back 

 upon itself at the end, it and the com- 

 mencement of the vas deferens forming 

 roughly a sort of compressed S. Unless 

 (as is surely not probable) we have here 

 two species confounded together, the value 

 of these characters for separating si)ecies is 

 evidently not so great as has been supjiosed. 

 It will only be by the dissection of many 

 specimens that the con^,tancy, or otherwise, 

 of these anatomical characters can be ascer- 

 tained. 



(1/') Subsp. celticus, Pollonera. Length (in 

 alcohol) 14 mill.; mantle, 5 mill, long; 

 respiratory orifice, well anterior. Sole 

 yellowish, unicolorous, finely obliquely 



striate, not differentiated into parts. 

 Mantle oval, the broad end posterior, 

 dark grey, with blackish lateral bands, 

 rather going over than surrounding the 

 respiratory orifice. Body grey, the sides 

 paler but dark reticulate ; blackish 

 lateral bands, bordered above by a 

 palish band. Rugte flattened. The 

 lineoles on foot-margin not much darker 

 than the margin itself 



Described from three alcoholic specimens 

 kindly sent to me by Mr. Pollonera, col- 

 lected at Brest, France. So far as external 

 characters go, I see no specific difference 

 from hortensis. For the anatomy, see 

 "Pollonera Atti. Ace. Sc. Torino," 1887, 

 p. 19, and figs. 



2.— Arion circumscriptus, Johnst. 



--■= fasciati/s (pars), Nilss. 



{2a) Subsp. bourguignati, Mab. Usually 

 distinguished at once from A. hortensis 

 by its white sole. A specimen of 

 hour!^iiii:;!iati, compared with the white- 

 soled variety of hortensis, was still easily 

 distinguished by its grey back mottled 

 with blackish, and the absence of the 

 pale yellow minute specks of hortensis. 

 The keel, also, is pale, and the edge of 

 the foot sublineolate. This si)ecies is 

 common in most parts of the British 

 Isles. Mr. Pollonera sent me three 

 specimens from Ceresole Reale, Piemont. 



Form. nov. atripunctatus, with numerous 

 black points on the mantle. Found 

 by Mr. G. Roberts at Lofthouse, York- 

 shire, May, 1887. 



{2l>) Subsp. ambigUUS, Pollonera. See 

 "Pollonera Atti. Ace. Sc. Torino," 1889, 

 p. 15, and figs. 



Var. armoricana, Pollonera. Specimens 

 found at Sturminster Marshall, Dorset, 



