300 



Records of the Indian Museum. 



[Vol. XIII, 



proximal part of the rostrum is altogether unarmed ; the hind- 

 most tooth of the series is placed above the cornea, when the eye 

 is directed straight forwards, or is in advance of this point. On 

 the lower border there are from i to 4 teeth, usually 2 or 3. 



The proportionate measurements of the legs are much the 

 same as in the typical form. In the first pair (text-fig. 2a) the 

 carpus is from 2T to 27 times as long as broad and in the second 

 (text-fig. 2b) from 56 to 6-3 times. The propodus of the third 

 pair (text-figs. 2c, d) is from 2*4 to 2"j times the length of the 

 dactylus, the length of the latter segment, spines excluded, being 

 from 3-3 to 40 times its breadth. In the fifth pair (text-figs. 2e, /) 

 the propodus is from 2*4 to (in one instance only) 2"9 times as long 

 as the dactylus, the latter segment, spines excluded, being from 

 4*o to 47 times as long as broad. The dactylar spines seem to 

 be rather more numerous than in the typical form ; in tlie third 

 pair there are from 24 to 30 and in the fifth from 71 to 92. 



In large males the third and fourth peraeopods show an extreme 



degree of sexual modification 

 (text-fig. 3). The propodus is 

 very strongly expanded distal- 

 ly, so much so that the seg- 

 ment is less than 5 times as 

 long as broad, whereas it is 

 nearly 9 times as long as broad 

 in females. The anterior mar- 

 gin is concave, while the poste- 

 rior is convex and is furnished 

 with numerous spinules in the 

 distal two thirds of its length. 

 The, dactylus is also modified ; 

 it is more than 5 times as long 

 as wide and is widest near the 

 distal end; the spines are dis- 

 tinctly recurved and the termi- 

 nal one is not larger than the 

 others. 



The subspecies appears to be 

 rather larger than the typical 

 form, reaching a maximum 

 length of 36 mm. The eggs vary from 063 to 070 mm. in length 

 and from 0-43 to 0*46 mm. in breadth. 



In this case I believe that the character of the rostrum affords 

 a valid basis for racial distinction ; among fifty specimens of the 

 subspecies I have not been able to find a single individual that 

 resembles the typical form. The specimens examined are from 

 the lagoon Kasumi-ga-ura in Hikachi province, collected by Dr. 

 N. Annandale; from Tokio, collected by Hilgendorf (Berlin Mus.) ; 

 from Lake Haruna, near Ikao, at an altitude of about 3000 ft., 

 collected by Dr. K. Nakazawa and from Lake Suwa, in the Shinano 

 province, at an altitude of 2660 ft,, collected by Dr. T. Kawamura. 



FiCx. 3. 



^ubsp. 



-Paratya compressn 

 proviso, nov. 



Third peraeopod of adult male with dacty- 

 lus further enlarged. 



