ZOOTECUS. 367 



with conic summit or cylindric tapering, composed of 7 to 10 

 compactly coiled whorls, the last rounded below ; striate or decus- 

 sate, glossy. Summit conic, entire, the protoconch striate like the 

 following whorls, not bulbous. Axis slender and straight, narrowly 

 perforated throughout. Aperture small, widely ovate, the peri- 

 stome thickened, blunt, columellar margin straight or concave, with 

 reflexed edge, continuous with the basal lip. Reproduction 

 viviparous. Dentition Achatinoid." (Pilsbry.) 



TYPE, Pupa insularis. 



Range. Cape Verd Isles and the Sahara eastward to Arabia, 

 India, and Burma, chiefly in arid or barren regions. 



" A group of small, Pupiform snails, largely eremitic in habits, 

 generally occurring in large numbers, and varying within wide 

 limits in size and degree of taper. Most gatherings from one 

 place show shorter and longer individuals, as in Holospira and 

 Cerion ; the diameter remaining more constant for any one colony. 

 The proportion of diameter to length is therefore individually 

 variable. There is a good deal of local variation in size and 

 texture, and hence a superabundance of names. 



" The group was instituted by Westerlund as a section of 

 Bull-minus. Kobelt, in his great monograph of the Buliminidce, 

 also leaves Zootecus therein, though uncertain as to its position. 

 Bourguignat struck nearer the mark in referring the species to 

 Ruinina, for I find the dentition to be of the Stenogyroid type. 

 It is, however, not closely related to Rumina, which differs 

 markedly by its smooth, globose protoconch and attenuated, 

 cylindric, subsequent neanic whorls. Riebeckia is perhaps the 

 nearest akin to Zootecus. Opeas and its brood belong to another 

 line of differentiation. 



" Captain Hutton found the large Indian form (pullus) to be 

 viviparous, three or four young shells lying in the oviduct. I 

 have confirmed this by opening dry shells of Z. insularis. The 

 young are ovate-conic, perforate, of two or three whorls, and like 

 the adults have the columella entire below. 



"There seems to be only two well-marked species, but 

 Z. insularis has a multitude of local races." (Pilsbry.) 



Yon Martens figured and described the jaw and radula of 

 Zootecus insularis and Z. pullus, attributing them to the genus 

 Stenogyra. He observes, moreover, that the name Zootecus should 

 be spelled Zootocus, but this procedure is inadvisable as the name 

 would in that case clash with Zootoca, Wagler, 1830 (Eeptilia), 

 and I prefer, therefore, to adopt Westerlund's mode of spelling, as 

 Pilsbry has done. 



333. Zootecus insularis, Ehrenberg. 



Pupa insularis, Ehrenberg, Symb. Phys. Anim. Evert, ser. 1, Moll. 

 1831, decasprima, signature d, third page ; Pfeiffer, MOD. Helic. 

 Viv. ii, 1848, p. 307. ' 



