COLLECTED IN DUTCH NEW GUINEA. 291 



grooves that cut up the surface into a number of quadrate blocks or masses of 

 epidermal tubercles or rugosities. 



Eight and left dorsal loles are found, while remote on the left-hand side of the 

 mantle is found a very narrow elongate pallial projection that possibly represents the 

 dorsal shell-lobe. Whether this is rudimentary or in process of development it is 

 difficult to decide. The author is also a little uncertain as to the correct interpretation 

 of the two lobes already described (PI. XXXII. fig. 4 a). 



The shell (PI. XXXIII. fig. 6 a, b, c) is of a rich dark chestnut-brown, scarcely 

 varying in hue between apex and umbilicus, though portions of the apex are decorti- 

 cated and discoloured. There are 4|^ whorls, increasing regularly in size, somewhat 

 polished in texture, crossed transversely by irregular growth-lines, which are often 

 broad and separated by wide intervals, with their ends somewhat indenting the suture 

 of the last whorl. On the apical whorls a faint spiral grooving is seen, and the growth- 

 lines are accompanied by a fine transverse striation. The apex is only moderately 

 prominent. The last whorl is bluntly carinate at its upper end, and the keel so formed 

 is slightly tuberculated by the broader growth-lines. The aperture is rounded, 

 moderate in size, and the lips are simple. The umbilicus is very slightly perforate, 

 while the columella is gently curved in accordance with the form of the aperture, 

 and is scarcely reflexed. On the under surface very faint traces of a spiral grooving 

 are found. 



Size: 16 mm. br.xlO mm. alt. 



B. Internal Characters. 



The /aw (PI. XXXII. fig. 7) is simple and strongly arcuate, with a prominent median 

 projection. 



The radula (PL XXXII. fig. 3). — Owing to the excessively close crowding of the 

 aculeate marginal teeth, it is impossible to speak with absolute certainty as to the formula. 

 The following, however, is approximately correct : — 120 . 14-15 . 1 . 14-15 . 120. 



The median tooth is tricuspid, with a large median cusp and a broad basal plate. 

 The laterals are, properly speaking, bicuspid, though the admedian members of the 

 series are so squarely shouldered on their upper internal angle as to give the imrpession 

 of a third cusp at that point. At about the tenth tooth of this series the main cusp 

 begins to slant inwards and becomes elongate and [dagger-like, and the whole tooth 

 becomes narrower until after the transitional 13-15, when a simple sabre-like tooth is 

 found. It is very difficult to make out the basal portion of these teeth, so closely are 

 they set, though the character indicated in the drawing is probably correct. 



Genitalia (text-fig. 6). — The penis is broad and moderately long. Internally it 

 bears a main seminal groove with several accessory grooves, all of which are thrown 

 into a number of folds at the distal (epiphallic) end (text-fig. 5). An epiphallus is 

 found, of moderate length and terminating in a broad stout retractor. The long 



