[No. 3, 
2GG F. Stoliczka — On the Cyclostomacea of Penang. 
Penang form it is directed backwards, being sometimes when well preseved 
perfectly parallel to tbe 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) roach the adult stage already at even a somewhat 
smaller size. 
Ilab. 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 lohe 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. 
OpiSTHOPomrs solutus, n. sp. PI. X, Figs. 8-10. • 
O. testa planorbulari, apice paulo exserta, late wmbilicata, corneo soli- 
dula ; anfractilus 4'5, fere teretibus, supra et infra paululum depress- 
imculis, suturn profunda acsimplici junctis, in spec, junioribus ad peripheri- 
ani suh-angulatis ; ultimo ad lerminationcm dissolulo, paulo expansiusculo 
modiceque deflexo, tubulo suturali antice directo, drciter 2 m.m. a margine 
aperturali distanle, instructo ; anfraclibus superioribus epidermide fusco- 
olivacea, transversim rugata, in ultimo fere simpliciter confertimque striolata, 
indutis, omnibus sub epidermidem albidis, sparse scrobiculatis, transverse 
minutissime striatis ; apice albido ; umbilico magno, anfractuum omnium 
maxvmam partem exhibente ; apertura lata , circulari, peristomate duplici, 
inferno tenui, paulum proficients, externo undigue rnodice dilatato, in facie 
antica concaviuscalo cl concentrice striato, in regione supra-suturali sensim 
producto ; atnlobus ad suturam anguste emarginatis. Operculum normale, 
in utroque latere vix concavum, multispiratum, medio corneo-solidum. 
Piam. maj. 15’5 ; diam. min. 11'5 ; alt. testae 7'3 ; diam. apert. int. 4'3, 
ext. cum per ist . 5'5 m.m. 
Young 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, 
