DRYM^US-ZAPLAGIUS. 187 



Helix navicula WAGNER, in Spix, Testacea Bras., p. 22, pi. 15, f. 

 2, 3. Bulimus navicula DESH., in Lam., An.s. Vert.,viii,p.256; in. 

 Fer., Hist., ii, p. 108, pi. 152, f. 9-12. PFR., Monogr.,ii, p. 99 (in 

 part) ; iii, p. 377. REEVE, Conch. Icon., pi. 41, f. 258b. Otostomu* 

 navicula BECK, Index, p. 55. Navicula fasciata SPIX, Mss. Test. 

 Bras, and on pi. 15. Bui. (Otostomiis) navicula CLESS., Mai. BL 

 (n. F.) x, p. 167. 



A well known species. In one specimen before me the base is con* 

 rex, basal angle rounded, obsolete, and the band wanting on the 

 spire. A broad basal band, as shown in fig. 19, is developed in 

 about 33 per cent, of the specimens examined. 



D. INVOLUTUS (von Martens). PI. 27, figs. 20, 21, 22, 23. 



Shell rimate-perforate, obliquely conic, carinate, white and shin- 

 ing. Whorls 5, the upper slightly convex, lightly striatulate, opaque 

 white; last whorl encircled at the periphery by a prominent thick 

 keel, latticed-malleate above and below the keel, the base convex. 



Aperture subvertical, ascending to the apex of the shell, triangular ^ 

 peristome thin, narrowly expanded throughout. Alt. 15, greater 

 diam. 30, lesser 18* mill. (Martens}. 



Bahia (Kahne). 



Bul'nmdus involutus MARTENS in Malakozool. Blatt., xiv, 1867, 

 p. 63. PFK., Monogr., vi, p. 81. Otostomus involutus MARTENS,. 

 Conchol. Mittheil., ii, p. 15, pi. 41, f. 1-4. 



Von Martecs further writes : " Nearly allied to B. navicula, hut 

 the last whorl ascends more, rising to the upper whorl, and the 

 sculpture is conspicuously different. A broad band above and below 

 the carina shows some peculiar long-rectangular impressions ar- 

 ranged serially, like rows of windows on a building; below and 

 above these the surface is smooth, only with weak striation in the 

 direction of growth-lines, while in B. navicula the whole surface of 

 the last whorl has irregular impressions as though hammered. 

 Moreover, B. navicula shows only a blunt keel, and is somewhat 

 convex above it, quite flat beneath, while in B. iniolutus the keel 

 stands out like a girdle, the shell on each side of it being somewhat 

 concave. There are no distinct bands, and the apex is not roseate." 



Described from one broken example in the Berlin Museum. 

 Among old papers von Martens found a colored drawing of the 

 species, apparently this same specimen before it was broken, the 

 figures given being restored therefrom. According to this drawing 



