RATHBUN: DECAPOD CRUSTACEANS. 311 



but not so extended (toward the middle of the back) ; the teeth of the prehensile 

 edges of the fingers stronger, the enlarged teeth being more distinctly different in 

 size from the intermediate teeth. 



Potamon (Potamonautes) cunicularis (Westwood). 



Plate 4, fig. 3. 



Potamon (Potamonautes) cunicularis Rathbun, op. cit., 1904 (4), 6, pi. 15, fig. 10; 

 1906 (4), 7, p. 184. 



India: Teesta Valley, at junction of Teesta and Rungeet rivers, border of Bhu- 

 tan ; 1 g juv., 16 mm. long by 20.4 mm. wide. This specimen is considerably 

 narrower than the adult male and also shows other differences which may be due 

 to age. The epigastric lobes (forming the median portion of the postfroutal crest) 

 are a little more oblique; the middle part of the upper border of the orbit is hori- 

 zontal ; the furrow of the ischiognath is deep. 



If the identification be correct (no specimens are at hand for comparison), the 

 range of this Indian species is extended; it has not heretofore been recorded 

 from north of lat. 19° 23' N. 1 



Potamon (Parathelphusa) spiniger (Wood-Mason). 



Potamon (Parathelphusa) spiniger Rathbun, op. cit., 1904 (4), 6, pi. 17, fig. 1; 1905 

 (4), 7, p. 231. 



India : Jungle pond 20 miles southeast of Lucknow ; 1 <J 2 9 • 



Potamon (Parathelphusa) tridentatus (Milne Edwards). 



Potamon (Parathelphusa) tridentatus Rathbun, op. cit., 1905 (4), 7, p. 234, pi. 13, 

 (Potamonidae 11), fig. 2. 



Java : River Tjiliwong, in Botanical Gardens, Buitenzorg, 850 feet altitude ; 

 lo*5<?. 



The male measures 29 mm. long, 36.8 mm. wide, 22 mm. between the outer 

 angles of the orbits, 10.2 mm. across lower edge of front. The greatest width is 

 behind the tips of the posterior of the lateral teeth. Occurs with P. convexus, but 

 distinguished at sight by its flatter carapace and larger teeth on the lateral mar- 

 gins ; comparing the largest males of both species, the abdomen is seen to be 

 much smaller in convexus; the sixth segment is about as long as its proximal 

 width in tridentatus, but distinctly longer than wide in convexus. 



1 This paper was in press before the publication of Alcock's work on the Pota- 

 monidae of India, and at the time of proof correction his memoir is not at hand for 

 comparison. 



