be of generic value. I am however now disposed to include both species in 

 the same genus. 



Occurrence. A solitary female specimen only of this pretty form has 

 as yet come under my notice. It was found in a sample taken at Riser in 

 about the same place, where Rhyncomyzon falco occurred. 



Distribution. British Isles (Brady), Mediterranean (Giesbrecht). 



Poecilostoma. 

 Fam. Lichomolgidae. 



Gen. Hermannella, Canu. 

 87. Hermannella dubia, n. sp. 



(PI. LXXIII, fig. 1). 



Specific Characters. Male. Anterior division of body rather broad, 

 sub-depressed, seen dorsally broadly oval in outline, with the greatest width 

 equalling -Is of the length and occurring in front of the middle. Cephalic 

 segment very large, fully twice as long at the 3 succeeding segments com- 

 bined, and evenly rounded in front, exhibiting behind the middle a well- 

 marked transverse suture. Last trunkal segment very small. Tail about equalling 

 in length z l?, of the anterior division, and composed of 5 well defined seg- 

 ments, the 1st of which (the genital segment) is very large and expanded, 

 almost circular in outline, exhibiting on each side a roomy chamber for the 

 reception of the spermatophores; the remaining segments narrow cylindrical 

 in form, the last being the largest. Caudal rami about 3 times as long as 

 they are broad and scarcely at all divergent; seta of outer edge attached in 

 the middle; apical setae partly brocken in the specimen examined, but appar- 

 ently normal. Anterior antennae less slender than in the other known species, 

 scarcely exceeding half the length of the cephalic segment, and only composed 

 of 6 joints. Posterior antennae not very strong, and composed of 4 well-defined 

 joints, the 2nd of which is the largest; 3rd joint armed at the end anteriorly 

 with a hook-like spine accompanied proximally by 2 small bristles; last joint 

 of about same size and provided at the tio with 4 curved claws, 2 of which 



