KOOTECUS. 



367 



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

 compacthj coiled whorls, the last rounded below ; smate or decus- 

 sate, olossy. Summit conk, entire, the protoconch striate like the 

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

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

 storm thichened, blunt, columellar margin straight or concave, with 

 reflexed edge, continuous with the basal hp. Eeproduction 

 viviparous. Dentition Acliatinoid.'" (Pilsbry.) 



Type, Pupa insuhrris. 



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 \N'ithin wide 

 Emits 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 

 \ariable. 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 

 Bidlminm. Kobelt, in his great "monograph of the Bidiminidce, 

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

 Bourc'uic^nat struck nearer the mark in referring the species to 

 liwntna'^ 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 neanie whorls. Miebeclia is perhaj^s the 

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

 Hue of differentiation. 



" Captain Hutton found the large Indian form {jndlus) to be 

 A'iviparous, 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 hke 

 the adults have the columella entire below, 



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

 Z insidaris has a multitude of local races." {Pilsbry.) 



Von Martens figured and described the ]aw and radula of 

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

 Stcno(/yra. He observes, moreover, that the name Zootecus should 

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

 wouhl in that case clash with Zootoca, AVagler, 1830 (Eeptilia), 

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

 Pilsbry has done. 



333. Zootecus insularis, Ehrenberg. 



Pupa insularis. ]]hrenbei'g, Symb. Phys. Anim. Evert, ser. 1, Moll. 

 1831, decas prima, .signaUire d, third page ; Pfeiffer, Mou. Hehc. 

 Viv. ii, 1848, p. 307. 



