SCIENCE-GOSSIP. 



77 



the parietal armature was figured has the outer 

 wall of the last whorl broken away ; in a second 

 specimen — not quite mature — this portion of the 

 outer wall is also missing ; the upper horizontal 

 fold in the latter specimen is very short, and the 

 third (anterior) transverse fold has not been formed 

 {see fig. iOi\b). A third specimen is entire ; but, as 

 the shell is somewhat translucent, I was enabled by 

 wetting it to make out the conformation of its 

 palatal armature without much difficulty, and 

 the figure I have given of it represents 

 these structures as they would appear if 

 looked at from the inner side (see fig. 104a). It will 

 be seen that the first (upper) fold is almost horizontal ; 

 the second is longer, a little deflected posteriorly, 

 where it is also attenuated, but truncated anteriorly ; 

 the third is shorter, oblique, curved ; the fourth sub- 

 vertical, bilobed at its middle, and furnished on the 

 posterior side with two small denticles, one near its 

 middle, and one near its lower extremity ; the fifth is 

 sub-horizontal, and has its two extremities a little 

 deflected ; a little denticle occurs near its posterior 

 extremity. From these features, hitherto unrecorded, 

 it will be seen that this species belongs to the group 

 of P. ponsonbyi, its nearest ally being P. leucochila 

 (Science-Gossip, iv., p. 231, fig. 66). Since the 

 foregoing remarks were written, I have been so for- 

 tunate as to acquire a specimen of P. feddetii, appar- 



ently communicated by Mr. Hungerford to Mr. 

 Langdon. This specimen, also, has only two trans- 

 verse parietal folds, so that it is somewhat uncertain 

 whether the third (anterior) transverse fold is of any 

 diagnostic value. 



Plectopyhs shauensis (fig. 105.) (See Science- 

 Gossip, iv. , p. 36, fig. 48). I append a figure acci- 



Fig-. 105. — Plectopyhs shanensis. 

 dentally omitted, giving a view of the shell, with ]art 

 of the outer wall removed, exposing the parietal 

 armature. 



Mr. Ponsonby has drawn my attention to an erron- 

 eous statement on page 17, with regard to his speci- 

 men of P. biciliata which, he informs me, was not 

 collected by Mr. Collett, but came from the Morelet 

 Collection, labelled as from Neville. 



All known forms of Plectopylis have now been con- 

 sidered ; and I propose to conclude this series of papers 

 with a synopsis, a key to the species, a map showing 

 their geographical distribution, and a general index. 

 t^To he continued.) 



