1881.] LAKES TANGANYIKA AND NVASSA, ETC. 283 



the author are those of an adult specimen ; and the aperture is pro- 

 portionally longer. In the present species the coloration is rather 

 different, and the epidermis is of an olive tint instead of rich fulvous 

 brown. 



15. AcHATiNA CRAVENi. (Plate XXXIII. fig. 11.) 

 Achatina Icirlcii, E. A. Smith, Ana. & Mag. Nat. Hist. 1880, 



vol. vi. p. 428. 



Shell elongate ovate, somewhat acuminate above, beneath a 

 yellowish epidermis white, ornamented with suberect, slightly wavy, 

 brown stripes. Whorls 8-9, rather convex, rather coarsely gra- 

 nosely sculptured ; suture between upper whorls horizontal, between 

 two last more oblique ; last whorl descending, smoother upon the 

 lower part. Aperture subpyriform, bluish white, occupying less 

 than half the shell. Columella not much arcuated, whitish, rather 

 abruptly truncated, connected with the upper extremity of the 

 outer lip by a thin callosity. Length 81 millims., diam. '67 ; aper- 

 ture 39 long, 20 wide. 



Hab. Between Zanzibar and Lake Tanganyika (Kirk). 



The granose surface of this species is the result of the coarse 

 raised lines of growth being crossed by transverse im])ressed striae, 

 which being somewhat remote from one another cause the granules 

 to assume a rather elongate form. Mr. Alfred E. Craven informs 

 me that the distinguished name of Dr. Kirk has already last year 

 been associated with a species of this genus. Such being the case, 

 I am compelled to alter the designation originally applied to this 

 species ; and therefore I have much pleasure in substituting that of 

 Jl. craveni. 



16. Achatina thomsoni. (Plate XXXIII. fig. 12.) 

 Achatina thomsoni, E. A. Smith, Annals, loc. cit. 



Shell moderately solid, elongate ovate, beneath a yellow epidermis 

 whitish, striped with blackish brown. Spire sometimes purplish 

 red or whitish, more or less worn, and in consequence, to a certain 

 extent, lacking the striping ; the latter is, as a rule, rather regular 

 and only a little wavy. Whorls 7, a little convex, striated by the 

 lines of growth, covered by a thin yellow epidermis, which is beauti- 

 fully sculptured with most minute striae in a crisscross fashion, 

 producing the woven appearance of a fabric ; last whorl elongate, 

 narrow, gradually descending. Aperture pyriform, bluish white. 

 Columella arcuate, thickened, not very abruptly truncated at the 

 base, united to the lip by a thin callosity. Length 75 millims., 

 diam. 32; aperture 38 long, 21 broad. 



Sab. Between Lake Nyassa and east coast (Thoinson). 



This species is remarkable for its narrow ovate form and the 

 peculiar woven appearance of its epidermis. The proportion of the 

 length of the aperture to that of the entire shell varies ; in some 

 specimens it occupies rather more than half the total length, and in 

 others somewhat less. The deep-brown or black stripes edged with 

 brown, as a rule, occupy more of the surface than the yellow spaces 



ly* 



