188 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Zua subcylindrica, TRYON, Am. Journ. Conch., III. 299 (1868). 



Cionella subcylindrica, W. G. BINNEY, L. & Fr.-W. Sh., I. 224 (1869). GOULD 



and BINNEY, Inv., 431, Fig. 690 (1870). 

 Ferussacia lubrica, PFR., Mon., VI. 245 (1868). 

 Bulimus lubricoides, STIMPSON, Sh. of N. E., 54. 

 Bulimus subcylindricus, MOQUIN-TANDON, Moll. Fr., II. 304, PI. XXII. Figs. 



15-19. 

 Zua lubricoidca, MORSE, Journ. Portl. Soc., I. 30, Figs. 79, 81, 84 ; PI. X. Fig. 



82 (1864) ; Arner. Nat, I. 607, Fig. 49 (1868). 



From Canada to the Red River of the North, and'English River ; in Ne- 

 braska ; in New England and the States bordering the great lakes. Thus it 

 belongs to the Northern Region of the Eastern Province. In the Central Prov- 

 ince it has been found in Colorado, at Fort Wingate in New Mexico. In the 

 Pacific Province in California and in Alaska. It is a circumpolar species, 

 common to the three continents. In Europe it is found in Spain, Italy, and 

 Illyria, as well as the extreme northern countries. PfeiSer also quotes it from 

 Madeira. 



Animal : head, back, and eye-peduncles blue-black, foot paler, shorter than 

 the shell ; tentacles short. (See Fig. 93, p. 180.) 



This little species, which is hardly larger than a grain of wheat, is certainly 

 identical with the European shell. It is distributed over a vast expanse of 

 country, and exists in immense numbers in certain favorable localities. Its 

 usual place of abode is under leaves and the bark of decaying trees, in forests 

 and groves. Its surface has a peculiarly brilliant reflection, which excels that 

 of any other of our shells ; and hence it has been known in France as " la bril- 

 lante." There is a slight sinuosity at the union of the peristome with the 

 columella, rendering the aperture a little effuse at this point, and approximat- 

 ing the shell to the genus Achatina. This, and its other departures from the 

 typical Bulimuli, have caused it, in several instances, to receive a generic 

 distinction. Dr. Leach first indicated it as a separate genus, under the name 

 Zua. 



My study of the membrane confirms my belief of the identity of the species 

 with the European form (see p. 187). I have carefully compared the dentition 

 of our form with that described and figured by Lehmann (Lebenden Schnec- 

 ken, 132, PL XIII. Fig. 44), and find them to agree. I must, therefore, disa- 

 gree with the decision of Morse (Journ. Portl. Soc.). I have also examined 

 the genitalia of our species, and found it to agree with Lehmann's figure (1. c.), 

 expecially in the existence of the very peculiar flagellum to the penis sac. 

 This, however, cannot be considered as a most reliable specific character pecu- 

 liar to this species, as it exists also in Coecilianella acicula. 



I am very confident of the presence of well-developed side cusps to the 

 central teeth, which Morse (I. c.) does not figure, though they are figured by 

 Thomson, Ann. Mag. N. H., VII., PI. IV. Fig. 8. They appear to me also to 

 bear the short cutting points which I have figured. 



