from the Chinese Seas. 359 



Length 27 millim. ; width across keels 3'8, width between 

 keels 2-6. 



Loc. Ashinojuj Japan [Hoist Coll.).'] 



These four species may be recognized as follows : — 



a. Of large size, with long legs and antennas ; the anal 

 sternite furnished with two very large tubercles ; 

 the anterior angles of the keels rounded and 

 convex. 

 «\ The anterior border of the keels convex and 

 produced forwards beneath the keel of the pre- 

 ceding segment, the posterior border evenly 



arched ; very wide : . . com^jactus, sp. n, 



¥. The anterior border of the keels not produced 

 forwards, but running backward from their 

 point of origin ; the posterior border armed with 



a triangular tooth ; much narrower ilentiyer, sp, n. 



h. Not so large, legs and antennae shorter ; anal 

 sternite oval or convex, not bifid ; anterior angles 

 of the keels squared. 

 a^. Keels very wide, with the anterior border con- 

 vex in its basal half Moorei, sp. n. 



¥. Keels much narrower, the anterior border 



straight or nearly so from the base to the angle, paludicola, sp. n. 



Polydesmus cruentatus, L. Koch (Verh. z.-b. Wien, 1878, 

 p. 795), from Japan, appears to belong to the same category 

 as P. compacfus and dentiger, inasmuch as its author mentions 

 the enlarged tubercles on the anal sternite. In measurements 

 it agrees closely with dentiger ; but no tooth is described as 

 occupying the posterior border of the keels, while from com- 

 pactus it seems to be separable by its more slender build and 

 by the sculpturing of the first dorsal plate. 



Fontaria lacustris^ sp. n. (PL XL figs, 8-8 h.) 



Colour (? faded) pale yellowish white throughout. 



Terga smooth, laterally above the keels lightly wrinkled or 

 coriaceous ; keels rather large, the anterior angle rounded, 

 the posterior rectangular or acute, but not dentiform ; the 

 anterior edge of the keel with a small basal shoulder, the 

 posterior edge emarginate, with a larger basal shoulder. 



Sterna and coxge of the legs studded with long hairs. Anal 

 sternite furnished with a median backwardly projecting spini- 

 form process. 



Copulatory feet diverging externally from the base, each 

 terminating in two processes — the inferior simple, pointed, 

 curved like an S, the superior inwardly directed, bifid. 



Length 20 millim. ; width across keels 3*5, width across 

 cylindrical part of segment 2 6. 



Loc. Wo Lee Lake, 25 miles S. of Ningpo [Bassett- Smith). 



