266 P. Stoliczka — On the Cgclostomacea of Penang. [No. 3, 



Penang form it is directed backwards, being sometimes when well preseved 

 perfectly parallel to tlie suture ; in a few specimens, however, it is nearly- 

 vertical, and in two or three even slightly directed forward. The character 

 is, therefore, evidently variable. Young shells, sometimes measuring up to 

 9 mm. in the longer diameter, still have no sutural tube developed, while 

 others (mostly males) reach the adult stage already at even a somewhat 

 smaller size. 



Hob. I found the species common under dead leaves on the ground 

 along the base of the Penang hill, mostly in dense jungle. 



Animal stout, blackish, sometimes mottle with grey and tinged with 

 pink, nearly smooth, with few little warts, paler at the sides and at the end 

 of the foot which is, when fully extended, about twice the longer diameter of 

 the shell ; it is pointed at the end ; operculigerous lobe slightly more 

 thickened in front than behind ; tentacles paler at base, blackish on terminal 

 half, slightly thickened towards the end, but pointed terminally ; eyes small, 

 on laterally slightly prominent bulgings, united to the base of the tentacles ; 

 rostrum wrinkled, cleft in front, and with pale lips ; penis of male long, 

 thin and black, without any appendage. 



Opisthopoeus soltttus, n. sp. PI. X, Figs. 8-10. 



O. testa planorbulari, apice paulo exserta, late umbilicata, comeo soli- 

 dula ; anfractibus 4'5, fere teretibus, supra et infra paululum depress- 

 iusculis, sutura profunda ac simplici junctis, in spec, junior ibus ad peripheri- 

 am sub-angulatis ; ultimo ad terminationem dissoluto, paulo expansiusculo 

 modiceque deflexo, tubulo suturali antice directo, circiter 2 m.m. a margine 

 aperturali distante, instructo ; anfractibus superioribus epidermide fusco- 

 olivacea, transversim rugata, in ultimo fere simpliciter confertimqibe striolata, 

 indutis, omnibus sub epidermidem albidis, sparse scrobiculatis, transverse 

 minutissime striatis ; apice albido ; umbilico onagno, anfractuum omnium 

 onaximam partem exhibente ; apertura lata, circulari, peristomate duplici, 

 interno tenui,paulum projiciente, externo undique modice dilatato, in facie 

 antica concaviusculo et concentrice striato, in regione supra-suturali sensim 

 producto ; amibobus ad suturam anguste emarginatis. Operculum normale, 

 in utroque latere vix concavum, miultispiratu/m, medio comeo -solidum. 

 Diam. maj. 15"5 ; diam. min. 11*5 ; alt. testae 7*3 ; diam. apert. int. 4 - 3, 

 ext. cum perist. 5 '5 m.m. 



Yomig shells of this species (comp. fig. 8) are regularly planorbular, 

 with a simple, continuous, thin lip of the aperture, and the olivaceous 

 epidermis is rather coarsely rugose, forming darker transverse bands ; under 

 the lens also a very fine spiral striation is to be observed. In the middle 

 stage (fig. 9), when the shells possess 3 - 5 to 4 whorls, and a diameter of 10 

 to 13 m.m., the margin of the aperture has a short, open, sutural canal, 



