Murdoch. — On Paryphanta atramentaria 313 



Art. XXXVII. — On the Anatomy of Paryphanta atramentaria, 



Shuttleworth. 



By R. Murdoch. 



{Read before the Wellington Philosophical Society, 1th December, 1905.] 



Plate XX. 

 An example of this handsome species was handed to the writer 

 by Mr. Charles Hedley of the Australian Museum, and for which 

 best thanks are here tendered. 



In shell characters this well-known Victorian species is 

 typical of Paryphanta ; the shell consists very largely of conchin 

 — in fact, with the exception of the apical whorls, consists almost 

 wholly of that substance. This is a feature quite in accord 

 with certain of the New Zealand and Tasmanian species. The 

 type of the genus, P. busbyi, Gray, is more largely built up[:of 

 calcareous matter than any other member of the group that 

 comes within my knowledge ; nevertheless, it is enveloped in 

 an exceedingly heavy coating of conchin. Suter* has drawn 

 attention to the predominance of this substance in the shells 

 of Paryphanta, and it appears to be the one prominent feature 

 characteristic of the genus, and by which it may be distinguished 

 from the nearly akin Fhytida. 



The animal (preserved in alcohol) is a deep-blue, with a 

 narrow area of yellowish-white around the margin of the foot. 

 The ruga? large, irregular, and not forming continuous rows. 

 On the dorsal surface of the neck are two prominent lines or 

 grooves which proceed from the head back under the mantle. 

 Upon the tail there appears to be no median groove, the ruga? 

 is a trifle smaller and less pronounced than on the neck and 

 sides. The footsole whitish, and contracted into numerous deep 

 folds — in life it is doubtless much expanded. The mantle- 

 margin yellowish-white, a somewhat prominent lappet at the 

 respiratory and anal pores, also a smaller one towards the left 

 side. The head of the animal is much drawn in, and the labial 

 projections are not discernible ; the tentacles are also completely 

 retracted. 



Internal Anatomy. — The buccal mass (figs. 1, 2) has the 

 usual form in this group of animals ; it is large and muscular, 

 with the posterior end curved down and forward. The retractor 

 muscle is a large, powerful structure ; it has no attachment 

 with the posterior end of the buccal mass, or, to be more correct, 

 what appears to be the posterior end (fig. 2), but is applied to 



* " Journal of Malacology," 1899, vol. vii, pt. 3, pp. 49, 50. 



