236 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



The jaw is as usual in the genus, wide, low, with about thirteen broad, sep- 

 arated ribs, denticulating either margin. The lingual membrane is as usual. 

 Teeth, 48 — 1 — 48. The characters of the teeth are sufficiently shown in my 

 Fig. G, of PI. V. The change from laterals to marginals is very gradual, the 

 latter being but a simple modification of the former. 



The genitalia (PI. XII. Fig. E) are very much like those of A. niger^ espiJ- 

 cially in the shape of the penis sac, and the peculiar accessory organ (/>, ^), 

 probably a vaginal prostate. The genital bladder differs some- 

 Fig. 136. what in shape, and also the testicle. 



y^ |\ The rudimentary shell has decided concentric layers. The 



O'^^^^j caudal mucus pore is as in .^. Columbianus. 



Ariolimax Andersoni 1 see W. G. Binney, Ann. Lye. Nat. Hist. 



Caudal pore of ^f j^ y., XL 182, PL XII. Fig. 9 (1875). 



A. Andersoni. 



Should this not prove the species described as Arion Andersoni 

 by Dr. J. G. Cooper, it must receive a new name. It is a true Ariolimax^ 

 most nearly related to A. niger. The latter species wants the foliated reticu- 

 lations, and has its posterior termination more blunt, with a decided lateral 

 cleft at the mucus pore. 



PROPHYSAON.^ 



Animal limaciform, attenuated behind. Mantle anterior, small, obtuse be- 

 fore and behind, its margins free as far back as the cleft for the respiratory 



Fig. 137. 



Prophysaon Hemphilli, 



orifice, enclosing a simple, not spiral, subhexagonal shell, which is longer than 

 wide. A longitudinal line around the animal just above the edge of foot. No 



1 Animal limaciforme, postice acuminatum. Pallium antice positum, parvum, obtusum, 

 marginibus anterioribus liberis, testam simplicem, haud spiralem includens. Margo in- 

 fera animalis sulco longitudinali supra pedem posito instructa. Discus distinctus gres- 

 sorius nullus. Apertura respiratoria et analis ad raarginem dextram pallii paululum 

 anteriorem positte. Apertura genitalis ad latus dextrum, pone et infra tentaculum 

 oculigerum. Porus mucosus caudalis nullus.. 



Testa interna longa, subhexagonalis. 



Maxilla leviter arcuata, costis numerosis validis (in specie unica circa XV), confertis 

 munita ; marginibus denticulatis. 



Lamina lingualis ut in Helice constituta. Dentes medianae tricuspidatae, laterales bi- 

 cuspidatae, marginales quadrat®, irregulariter cuspidatae. 



Habitat in Oregon et in California. Specimina plurima coUegit H. Hemphill de Astoria 

 usque ad San Francisco, j 



