31 



ON THE ANATOMY OF HEMIPLEGIA FLO WERT, E. A. Smith, FROM 

 PERAK, MALAY PENINSULA; WITH NOTES ON SOME OTHER 

 EASTERN GENERA. 



By Lieut. -Col. H. II. Godwin-Austen, F.R.S., etc. 



Head 8th December, 1899. 

 PLATE IV. 



Hemiplegia Floweki, Smith. 



Early in the present year I received from Mr. Stanley Flower 

 a spirit specimen of this fine species, labelled Larut, Perak. About 

 the same time some shells had been presented to the British Museum 

 (Natural History), and were shown to me by Mr. E. A. Smith, who 

 described the species before this Society in March. In February 

 I began an investigation of its anatomy, but could not complete 

 the drawings in time for Mr. Smith's paper. These I am now able 

 to submit. 



External Features. — The living animal is apparently black, or 

 grey-black, and, judging from the wrinkled condition of its edge in 

 the spirit specimen, the foot probably spreads out thin and flat when 

 the animal is in motion, as seen, to name a striking instance, in the 

 large JEucochlias ochthoplax, Bens., the foot of which is often extended 

 till it forms a thin oval disc, giving great holding power. The 

 peripodial fringe is very marked, streaked with pale lines on the 

 black ground ; the parallel grooves so distinctive in many genera of 

 the Zonitidae are not apparent. 



The sole of the foot is not divided ; the whole surface is wrinkled 

 by contraction. This in life would probably be quite smooth, while 

 the mucous gland (PI. IV, Fig. 1) would apparently be broad and 

 open, without any very marked overhanging lobe. The mucous 

 gland does not extend to the sole of the foot. There is a right 

 shelblobe (Figs. 2 and 5), situated at a short distance below the 

 upper inner angle of the aperture ; also a well-developed left 

 shell lobe (Fig. 3), tongue-shaped, and given off from the narrow 

 peristomatic edge. The left neck-lobe is divided into two very 

 distinct and widely separated portions (Fig. 3). At the lower angle 

 of the aperture (Fig. 4), and corresponding with the dark band of 

 colour round the umbilical region, there occurs an expansion of the 

 shell-lobe, which we may term the ' umbilical, or columellar lobe,' 

 and the breadth of this is indicated by one or more shallow grooves 

 on the surface of the shell itself. There is also (as noted by 



