From the ‘PRocreDINGs or THE Mataconoarcan Socrery,’ VY ‘ 
Part 6, October, 1899. | ati 
ANATOMICAL NOTES ON MEDYLA INSCULPTA (Prr.). 
By Henry Soren. 
Read 9th June, 1899. 
Taroven the kindness of Mr. Laing, of Christchurch, New Zealand, 
who spent several months on N orfolk Island, I obtained a number of 
land-shells preserved in formalin, all, with one exception, being 
Mepyta (EKvupiecra) rscutpra (Pfeiffer). 
Helix insculpta, Pfeiffer: Proc. Zool. Soc., 1845, p. 129. 
A number of the shells contained the animal, though not in a very 
good condition for dissection. However, I was able to examine the 
dentition and the genital organs, of which I propose to give a short 
account. 
Animal.—With two short, broad shell lobes, the left divided into 
two; the foot (Fig. I) shows distinct diagonal and double parapodial 
erooves; there is a pronounced caudal pore, situated above the 
termination of the parapodial pore. The sole is tripartite. 
Jaw (Fig. Il). — Extremely thin and fragile, transparent, with 
a strong median projection on the cutting edge, the outline being 
repeated (as a remnant of an earlier stage of growth) a little higher up. 
Radula (Fig. III).— Formula 35-7-1-7-35. The minute outer 
marginals have an aculeate mesodont, denticulated on its posterior 
edge, with a small base of attachment; on the succeeding inner teeth 
the denticles, numbering from three to four, become successively more 
and more distinct, whilst just a little below the point of the mesodont 
an ectodont appears, consisting of two cusps, which are at first 
separate, but subsequently are united at the base. The marginals 
next gradually assume a triangular shape, and the denticles on the 
mesodont disappear, whilst the ectodont becomes simple and larger. 
A few transitional teeth lead to the asymmetrical laterals, each with 
a short and stout mesocone, extending to the posterior edge of the 
base, and a rather stout ectodont. The central tooth is tricuspid, the 
side cusps well developed, and the mesodont of the same length as on 
the laterals. als 
Genitalia (Fig. IV). — Simple, the lower portion consisting of 
a large, muscular, subcylindrical penis sac with a retractor muscle 
at its posterior end, where also the vas-deferens enters. At the 
anterior portion of the penis sac, near the atrium, an appendix 1s 
inserted which has nearly half the length of the former, and 1s 
slightly distended distally. The vagina 1s formed by a rather Lane 
muscular pouch, provided with a tubular receptaculum seminis on. : e 
side towards the common orifice, it 1s slightly bent, and does not widen 
