346 UR. E. A. SMITH ON SHELLS [Apr. 20, 



ill some specimens is almost black, predominates ; and the opaque, 

 obliquely somewhat zigzag stripes upon the back of the body-whorl 

 in several shells are abruptly terminated in an obhque line which 

 marks a period of growth. Between the larger creamy stripes which 

 reach from suture to suture in the upper whorls, and extend over 

 the whole extent of the last, there are minor streaks and spots flow- 

 ing only a short distance beneath the suture. 



I feel much pleasure in naming this species (perhaps only a 

 variety, but a very interesting one) after Professor Martens, of the 

 Berlin Museum, who, amongst his innumerable and valuable con- 

 chological papers, has written several upon the fauna of the Nilotic 

 region. 



3. AcHATiNA (Limicolaria) rectistrigata. (Plate XXXI. 

 fig. 2.) 



Shell oblong, cylindrically conical, narrowly perforate, whitish or 

 of a pale rosy tint, varied with obUque brown stripes, which at times 

 become broader or blotchy at the lower part of the whorls. The 

 latter are 8 in number, rather convex and slowly enlarging, obliquely 

 striated by the lines of growth, divided by a simple subhorizontal 

 suture. Last volution oblong, a little attenuated at the lower part. 

 Aperture inversely subauriform, whitish or pale rose within, equalling 

 rather more than one third of the entire length of the shell. Peri- 

 stome (viewed laterally) oblique, a little tortuous, thin at the edge, 

 and inconspicuosly thickened within. Columella spirally contorted, 

 bluish, and reflexed over the perforation at the upper part, brownish 

 interiorly, and gradually curving into the basal margin of the aperture. 

 Paries coated with a thin callosity. Length 44 millims., diam. 17 ; 

 a])erture 16 long, 8 wide. 



The peculiarity of this species consists in the ornamentation taking 

 the form of defined stripes, and not exhibiting a wavy or zigzag 

 tendency so common to most of the species of this grou]i of Achatina. 

 L. cailliaudi, Pfeiffer, and L. sennaariensis, Shutleworth, are allied 

 forms. 



4. BuLiMUS (BuLiMiNus) PTYCHAXis. (Plate XXXL fig. 3.) 



Shell elongate, turreted, perforate, thin, dirty white, covered with 

 a very thin, pale, sordid olive epidermis. Spire elongate-conical, 

 with a rather obtuse apex. Whorls 9, somewhat convex, divided by 

 a deepish suture, bearing fine, regular, oblique and slightly flexuous 

 costulse, which, upon the last whorl, become less pronounced from 

 the middle downwards. Aperture vertical, occupying about one third 

 of the length of the shell. Columella erect, reflexed over the um- 

 bilicus, bearing a fine oblique plait a little below the middle ; outer 

 lip thin and feebly expanded. Length 27 millims., diam. lOg ; 

 aperture 9 long, 5 broad. 



B. /aVAiof Dohrn, from Mozambiqtie, is sculptured very similarly to 

 this species. It is, however, much shorter, and does not possess a 

 columeilar fold. The latter is even more distinct in the young shell 

 than in the adult ; and the last whorl in the former exhibits a faint 



