ARIONTIhE. 231 



FAMILY AEIONID^. 



Animal with or without mucous pore ; mantle anterior, con- 

 cealing a shell-plate, or a few calcareous grains which represent 

 it; jaw strongly ribbed, central tooth tricuspidate, the median 

 cusp long and narrow, laterals and marginals bicuspidate. 



Synopsis of Genera. 



* With caudal mucous pore. 



Genus AHION, Ferussac, 1819. 



Animal naked, limaciform, subcylindrical, attenuated but not 

 carinated behind, rugose, with a caudal mucous pore; shield 

 granular, small, anterior, covering calcareous grains which are 

 sometimes agglomerated into the semblance of a shelly plate ; 

 locomotive disk distinct ; pulmonary orifice at the right anterior 

 margin of the shield, the genital orifice under it. Jaw (PL 44, 

 fig. 11) arcuated, strongly ribbed ; central tooth tricuspid, the 

 central cusp long and narrow, laterals bicuspid, marginals 

 bicuspid, the inner cusp long and narrow (PL 44, fig. 10). 



The species inhabit Europe and the north of Asia and Africa. 

 The " land soles " occasionally devour animal substances, such 

 as dead worms or injured individuals of their own species. 

 They lay T5-100 eggs between May and September, which are 

 26-40 days in hatching, and the snail attains its full growth in 

 a year, beginning to oviposit a month or two before that period. 

 The eggs of A. hortensis are very phosphorescent for the first 

 fifteen days. 



Section LOCHEA, Moquin-Tandon, 1855. Internal shell repre- 

 sented by isolated calcareous granules. A. rufus, Linn. 



Section CARINELLA, Mabille, 1870. Dorsally somewhat cari- 

 nate. A. Dupuyanus, Bourg. 



Section PROLEPIS, Moquin-Tandon, 1855. Calcareous granules 

 agglomerated into an imperfect shell-plate. A. fuscus, Mull. 

 Kobeltia, Seibert, is a synonym. 



Section BAUDONIA, Mabille, 1868. Body anteriorly enlarged 

 and depressed, the shield almost smooth, the head well separated 

 from the body, tentacles rather small. Two Portuguese species. 



