86 collinoe: non-opercut.ate land and freshwater molluscs. 



Museum collection from Peni^g marked " T". mm/uinea, Stol.," was 

 apparently referable to A. pulverulentus, Bens., and also gave a des- 

 cription of Prisma hpynenianni, Simr. 



In 1892 von Ihering (18) published a short, critical note on 

 Simroth's paper, and proposed a separate family — Afojiida/' — for the 

 genus. A reply by Sim roth followed (28). 



Nothing more was heard of these interesting molluscs until 1899, 

 when the Sarasins (25) in their beautiful work on the Land MoUusca 

 of the Celebes, described four new species of Afojjos, viz., A.srutuJafu-% 

 simrofhi, crii<fa(jalli and pi-istis, and gave some interesting notes on 

 their anatomy and figures of some of the internal organs. 



Lastly Babor (i) in 1900 described a new sub-genus — Padamjia — 

 for a new species, Afopos (PaihuKjia) tfchildii, from Padang, Sumatra. 



The opinions held by the different writers quoted above, as to the 

 affinities and systematic position of these various genera are widely 

 diverse. On the one hand Simroth and Babor are both inclined to 

 regard them as allied to the Vt'romrelUdae, while on the other von 

 Ihering and the Sarasins allie them with the TeMacellldae. 



Simroth (27) in his valuable paper first directed attention to certain 

 resemblences between Afojnn< and the Aflioracopihoridai' (JaneJlidap), 

 and he there states that the VeronkeUidae may have been directly 

 derived from the Opisthobranchia, the AfhorarojjJwridae diverging from 

 them at some period ; the two families he classes together as Mesom- 

 matophora, in contradistinction to the true Stylommatophora. Babor 

 (i) also hints at the resemblences between the Athorarophoridae and 

 Padamjia. 



Von Ihering strongly supports the Testacellid relationship, entirely 

 overlooking the fact mentioned by Simroth, that the Testacellid tooth 

 structure, evolved as it is by necessity for adaptation to carnivorous 

 habits, has no anatomical value, as is evidenced by the great variety of 

 molluscs possessing such a tooth structure. 



The Sarasins regard Rafhouiftia and Afojio>< only as valid genera, 

 Prix>iia in their opinion not having been sufficiently defined, ^^'hilst 

 strongly favouring the Testacellid affinities of these two genera, the)' 

 admit that such characters may have arisen independently, as in 

 lanthina and Sccdaria. Further, these authors regard Apera, Heyn., 

 as also being closely allied to the Ji'athouiniidae, they write (25, p. 112) 

 " This slug, we can without hesitation look upon as an ancestral form 

 of Afopott." Unfi)rtunately the genus Apera is known to these authors 

 from Binney's original description and figures only. The spider-glands 

 of Simroth are not present in Apera, and the general disposition and 

 form of the digestive and generative organs, pedal gland, etc., is totally 



