[Proc. Rot. Soc, Victoria, 24 (N.S.), Pt. II., 1911.] 



Art. XXIII. — The Anatomy of the Slug, Cystopelta 

 petterdi, var. 'purpurea, var. nov. 



By olive B. DAVIES, B.Sc. 



(Government Research Bursar, Melbourne University). 



(With Plates LXIV-LXIX.). 

 [Read 14.th December, 1911.]. 



Since the description given by Mr. Hedley in 1890 no fur- 

 ther work has been done, so far as I can discover, on Cystopelta 

 petterdi. Professor Spencer and Mr. Hedley therefore suggested 

 that I should give a fuller acount of the anatomy of this animal. 



In the Biological Department of the Melbourne University 

 were some preserved specimens, some of which came from 

 Beech Forest, Victoria, and were preserved in spirit, and so 

 contracted as to be of no use for external description or dis- 

 section. These were used in sections, being stained with acetic 

 Acid alum carmine. The rest came from Fernshawe, Victoria, 

 and w^ere preserved in formalin. Later I found two living speci- 

 mens at Narbethong, Victoria. These I used for dissection and 

 external description. 



Professor Tate gave a short description of Cystopelta 

 petterdi in the Report of the Royal Society of Tasmania, 1880. 

 A description and drawing of the animal has also been given 

 by Mr. C. Hedley in the Proceedings of the Linnean Society of 

 New South Wales, 1890. 



External Features and General Description. (Fig I.) 



The animal is small and slug-like, with its organs drawn into 

 s, dorsal hump as in snails, but no spiral twisting is visible from 

 the exterior. The hump is very large, extending from just 

 behind the reproductive opening anteriorly, to overhang about 

 half the free portion of the foot posteriorly. In colouring, my 

 specimens resemble neither those described by Mr. Hedley nor 



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