Entozoa from the Murman Coast. 507 
about the fiftieth. The genital pores are situated near the 
front of the segment and irregularly alternating. There is a 
muscular genital atrium (fig. 4, G.A.) into which the cirrus- 
an) 
Fig. 3. 
Monopylidium arcticum; the scolex and anterior end of the strobila. 
A. An example with moderately contracted neck; G., paired glands (?) 
at base of rostellum. 
B. An example (less highly magnified) showing marked contraction of 
the neck, 
sac and vagina open. The cirrus-sac (fig. 4, C.S.). is very 
long and narrow, measuring 0°175 mm, in length and 
0:035 mm. in width. It curves forwards from the genital 
