174 THE CHICAGO ACADEMY OF SCIENCES. 
cool and damp, and affording shade from the sun’s rays. The 
banks of rivers are good localities. 
Remarks: This species is so distinct that it cannot be con- 
founded with any other. It is rather shy in captivity and 
quickly retracts within its shell when disturbed. It is nota 
common species with us, and has thus far been found in but 
few localities. Those in this area do not seem to congregate 
together in large numbers, as do many of our snails, but are 
found either singly or only two or three together. It is a per- 
fect cannibal, and will very quickly ‘clean out” a snailery of 
half a dozen or more common Helices. Thrusting out its long 
body it crawls into the shells of its victims, and no matter how 
far the latter may contract within their shells, it is of no avail 
against the carnivorous appetite of Czvcomaria. It may well be 
termed the tiger of the Molluscan kingdom. It preys uponits 
own as well as upon other species, thus being in truth a canni- 
bal. Thus far it has only been found in the northern and 
western regions. Concava has been found at Bowmanville 
under ‘‘starting” bark at a height of four feet from the ground. 
The animal is very nervous in progression, constantly extend- 
ing and retracting its eye-peduncles, the shell swaying from 
side to side with a wabbly motion. 
On May 18, 1897, two individuals were seen in copulation; 
the coitus lasting over ten hours (from 8 o’clock a. m. until 6 
o’clock p. m.); the eye-peduncles were almost drawn into the 
head, and the foot was contracted to form a long oval; the 
heart beat very slowly, nineteen pulsations being counted per 
minute (about eighty being normal) and the beats were very 
long. 
Superfamily Aulacopoda. 
‘Animal with well-developed pedal grooves. Shell sharp- 
lipped.” (Pilsbry.) 
FAMILY ZONITID. 
‘Marginal teeth with narrow, elongated basal-plates, and 
either unicuspid and thorn-shaped by suppression of side cusps, 
or bicuspid by elevation of outeron middle cusp. Tail gland 
often present, and sole frequently tripartite.’”’* | 
*Pilsbry, Guide to Helices, p. XXVIII. 
