SMITH : DESCRIPTION OF A NEW SPECIES OF ACROPTYCHIA. 23 



ridiculous, and tends merely to confusion and to bring the science 

 into contempt. 



The species I am about to describe is very much smaller than 

 A. metableta, but of a similar conical form, exhibits traces of a 

 deciduous epidermis, but has only a simple broadly expanded 

 peristome. Unfortunately, the operculum is wanting in the two 

 specimens examined, and therefore it is not quite certain that it 

 should be regarded as belonging to Acroptychia. If it possessed a 

 sutural tube it would be an Alycaus, for it has the constriction of 

 the body-whorl so characteristic of that genus. 



ACROPTYCHIA NOTABILIS. 



Testa turbinata, conica, umbilicata, saturate fusca, ad 

 peripheriam pallida ; anfractus 6, convexi, sutura subprofunda 

 discreti, lineis incrementi perobliquis flexuosis et striis spiralibus 

 microscopicis indistinclis ornaii, ultimus in medio rotunde 

 angulatus, hand ascendeus vel descendens, paulo pone aperturam 

 leviter constrictus, prope la brum tenue album et valde expansion 

 quadri-indentatus ; apertura subcircularis, fusca, zone pallida 

 dimidiata, pustulis quatuor intus instructa ; perist. tenue, vix 

 continuum, marginibus callo tcnui junctis, columellari ad 

 umbilicum sinuato, infra sin urn dilatato. Diam. mag. to mil/im., 

 min. jh, alt- 9- Apertura intus 3^ longa et lata. 



Hab. Madagascar, probably from the neighbourhood of Tamatave. 



The constriction of the body-whorl and the four indentations 

 between it and the expanded peristome, which have the appearance 

 of blisters within the aperture, readily distinguish this interesting 

 little species. The outlines of the spire are a little concave, and the 

 apex is large and obtuse. The epidermis in both A. metableta and 

 A. ccquivoca is more or less diaphanous, and the remains of a similar 

 periostracum is also traceable in the present species. The lamellae 

 in both the above-named forms are very sharp, flat, and at right 

 angles to the surface of the body-whorl, and the peristome in this 

 species is almost precisely of the same character, and differs only in 

 being more interrupted near the umbilicus. Another feature which 

 induces me to place this shell in Acroptychia is the presence of very 

 fine spiral sculpture, which also occurs in the two larger forms. 

 As a guide to the form of A. notabilis, reference may be made to the 

 figure of Alycceus galbanus, Godwin-Austen.* 



* Proc. Zool. Soc. (1S89), pi. xxxvii., f. i-ia. This gives a fair idea of the general form, but 

 of course has differences of detail. 



