MONOGRAPH OF mUTrSII LANI> ANH FlfESIIWATER MOtJJ'Sr'A . 



■ ^A, 

 , I'. 7 



Arion circumscriptus Johnston. 



ISlfl Arion Iiarlnisis var. a ami ft Funissac, Hist. Moll., |.l. -J, f. 0, ami jil 



IS'-S — circumscriptus Jolmstim, Kiliiil>iiri;li New I'liilds. .loiini., \-. 



1S37 — iiuinjhiatiis Kickx, IJull. Acad. Kcjy. Soc. Bru.-celles, iv. , p. 



1852 — lencophreus Noriiiaud, Descr. Six Liiiiae. Nouv., p. 6. 



1864 — hortensis var. grisea Bourguijinat, Malac. Gr. Cliarti., jil. 1, f. '.111. 



1868 — hoin-f/tiif/iuifi Mabille, Ilev. et -Mag. Zool., xx., p. l:is. 



1868 — ncntitriaru.-i JIaliille, op. cit. 



188.'i — (Cnri)iclla) boiinjiiiiinull PoUoneva, Moll. Terr. Pieuuiiite, p. 



1887 — (-(^^^^tc^s PoUonera, Siiec. Nuov. Arion Europei, p. 19, rt'. 11, -l: 



1887 — nilssoni PoUonera, op. cit., p. 19, ft'. 33-34. 



1889 — (tinhirjuns Polloiiera, Nuove Coutr. Arion Eui-opei, ]i. I.">, If. 1 



1890 — siiliairinatas Piillonera, lieeensieni. Arioniila" Palearct., p. L! 

 1822 Limax fctsciatus 7 Nilsson, Hist. Moll. Sveciae, p. 4. 

 1868 Pi-olepis hortensis Malm, Limac. Scand., pi. 2, f. ">. 

 1881 Gcoinalacus botirr/dirfiinti Loeard, Moll. Ain, p. 11. 



ir. 2-4. 

 (i. 



28. 

 2, 33, 



19. 



E- 



' ISTORY. — .1 rio)> (■irtuiuKcripfii^ 

 [circum, around; .sv/vy'/w;;/, marked) 

 ill iillusioii to the distinct lateral hlack 

 zone almost encircling the liody, is here 

 associated with the late Dr. (1. Jnhiiston, 

 of Berwick, the aiitlior of the e.xrellent 

 work, an " Introduction to Gonchology," 

 who first differentiated and named the 

 species. It is also ]irol]ahly the Ari/m 

 //orfi'iisis vars. n and fi of I'V'riissa.c a-iid 

 the LiiiiK.v j'ascidtiis va.r. y (if Nilsson, 

 and is said hy P(jllonera. U> he the same 

 as Cre^iiiin/drits hinjKiii .Timsseaiime a.iid 

 Arion dupuijaniis uf Biinrguigiiat, hut 

 the latter species is descrihed a,s pussess- 

 iiig a strong keel and yellowish fmt, 

 characters "which arc sniiicwhat against 

 this allucatiou. 



The sub-genus ('(irhiclhi has hceii 

 instituted by Maliille fm- the. reccptinu 

 of tlie present S2)ecics and clDscly-allicd 

 forms, a grouping based upim the pos- 

 sessi(j]i of a dorsal keel during the earlier 

 stages of growth, but which ma,y occasion- 

 ally jicrsist to adult life. 



Diagnosis. — Arion rirrtimscri/ifu.-< is larger, broader, and fir ])aler in 

 colour than A. liorfeii><i^, the siiecies with whicli it has been so long cnu- 

 founded. The distinctly white foot of the present s[iei-ies is also one of its 

 most striking characteristics. 



Internally, it is distinctly seiiarated from its ally, Arion horfcusir;, by 

 its very elongate and narrow .atriu.m, pointed SPEiiMATUEC.v, slcndci- and 

 rather uniform epiphallus, and shorter free oviliuot. 



Origfinal Description. — ^Iri'ni rin:i(iiisi-n/ifi/,s. IJoily ni'eyisli-blark, sjioltcd, 

 witli a lilack fascia round tlie shield and Imdy, the respii'atory a|iertnre anterioi-. 



Jiody, 1 or l'^ inch long, not keeled, nor much nariowed at IJii' tail ; gi'cyish- 

 Ijlack, marbled, with a naroiw fascia .surrounding the ha.ck and shield ; sides lilnish- 

 grey ; foot white, opai|Ue ; tentacnia rather shoit, hlack; rc's|iiiatmy a|icitnre 



