BY C. HEDLEY. 23 



Rhytida lampra, Pfeiffer. 



This carnivorous mollusc is generally distributed throughout 

 Tasmania. Mr. Petterd relates its cannibal propensities as 

 similar to those of its Queensland relative (P.R.S.Q., Vol. v., 

 p. 152). The specimen I examined measured, when expanded, 

 40 mm. from head to tail ; but I am informed that the species in 

 other localities attains larger dimensions. Colour, orange-brown 

 on the edge of the foot, passing through chestnut-brown to black 

 upon the head and tentacles, mantle-collar orange-brown. Down 

 the centre of the back runs a small groove from the shell to 

 between the tentacles, and on either side of this the facial area is 

 ornamented by three longitudinal rows of small round tubercles ; 

 tail and sides divided into irregular polygonal spaces which are 

 partially sub-divided and finely granulated. The tail is extremely 

 short, hardly passing the shell, while the anterior portion of the 

 body, as in other Agnatha, is capable of a leech-like extension, 

 a provision for enabling the creature to stretch itself into the 

 remoter whorls of a shell whose inhabitant it may be engaged in 

 devouring. Habits bold and active ; crawls more rapidly than 

 the HelicidcB usually do. The radula is constructed of 75 rows 

 of 40-0-40, is strap-shaped, measuring 15 mm. in length and 4 in 

 breadth, each half-row curving from the margin and meeting its 

 fellow at an acute angle in the centre of the ribbon ; the 

 rachidian (as is usual in the genus) has been lost, the two inner- 

 most laterals are usually rudimentary, but the third attains its 

 full development, having a basal plate the shape of the sole of a 

 man's foot and a straight slender cusp in the same plane, the 

 whole tooth resembling a clasp knife with the blade open ; the 

 teeth continue of the same size to the margin, the pattern differing 

 slightly by the basal plate of the remotest becoming triangular. 

 In the genitalia the penis-sac is slender; a sessile globose sperma- 

 theca is inserted upon a short pyriform vagina. 



