612 MAJOR GODWIN -AUSTEN ON [NOT. 17, 



animal could at once exude, would have the best chance of sur- 

 viving. 



Among the species of Plectopylis at the British Museum is one 

 labelled H. prodigium, Bs. (Mus. Cuming) ; this is undoubtedly 

 H.plectostoma, Bs., the former being very likely its first MS. name. 

 Plectopylis refuga, Gd., var. dextrorsa, I have not been able to ex- 

 amine ; but it probably will prove distinct. 



P. pettos, described (as Corilla) by Dr. Ed. v. Martens, Malako- 

 zoologische Blatter, 1868, p. 158, together with other shells from 

 the Himalayas, it is difficult to place in its true position in the genus, 

 owing to the internal structure having been left unnoticed. It would 

 appear to be very close in form of aperture to P. serica. I know of no 

 similar form from the Himalaya that would agree with the description. 

 H. pulvinaris, Gould, from Hongkong, to which it is said to approach, 

 is not known to me. 



I have been able to examine, by the kindness of Dr. Giinther, all 

 the species of the genus in the British Museum, among them P. re- 

 fuga, Gld. This is sinistrose. Whorls 6, with one long horizontal 

 parietal lamella, continuous to the apertural ridge, with two free 

 horizontal larnellse below it, the lowest being the longest, and situated 

 close to the simple vertical barrier ; below this is another moderately 

 long horizontal free lamina. The palatal plicae are 6, the four upper 

 lengthened ; the fifth is subvertical, and the sixth small. P. refuga is 

 very close to P. leiophis ; but in that species the long upper horizontal 

 lamella is united to the second and shorter one below. 



Characters of the Genus Plectopylis. 



[All these forms have a lower parietal free lamella, with the exception of 



those marked t.] 



Group A. Parietal vertical lamina simple. 



a. Horizontal parietal lamina none. 



a. Palatal plicce simple. 



1. sericat, G.-A. D. N.E. frontier, Naga HilLj. 



2. pinacis, Bs. S. E. Himalaya. 



3. munipurensis, G.-A. D. N.E. frontier, Bengal. 



4. laomontana\ , Pfr. D. Cambodia, Lao Mt. 

 laomontana, small var. Cambodia. 

 pettos, v. Martens ? Himalaya ? 



/3. Palatal plica? double, in two rows. 



5. macrompfudus, W. Blf. S. Darjeeling and N.E. frontier, 



Bengal. Khasi. 



6. plectostomaA, Bs. S., epiderm hirsute. Darjeeling and 



N.E. frontier, Bengal. Khasi. 



* United by low ridge. 



7. andersoni\, W. Blf. D. N. Burmah. 

 ** Posterior row strong, oblique. 



8. clatkratulaf. D. Kandy, Ceylon. 

 *** Posterior row strong, vertical. 



9. retiferat. D. Southern India. 



b. Horizontal parietal lamina present. 



* Single. 



10. nagaensis, G.-A. S. N.E. frontier, Naga. 



