y8 Records of the Indian Museum. [Vci,. X, 



Carapace not produced in the form, of a rostral plate ; lateral 

 corners acutely produced. 



Superior antennae of the usual structure but wanting the 

 hirsute appendage in the male. 



Antennal scale narrowly oval in shape, setose all round, un- 

 jointed. 



Telson short, entire, quadrangular in shape, lateral margins 

 armed with a few short spines; apex truncate, armed with a row 

 of small teeth. 



First, second and third pairs of pleopods in the male, as in the 

 female. Fourth pair distinctly biramous, inner ramus quite small 

 and bearing only a few delicate setae, outer ramus considerably 

 elongate, extending beyond the posterior margin of the last seg- 

 ment of the pleon, consisting of a single elongate joint terminated 

 by a long slender spiniforni seta. Fifth pair elongate, extending 

 beyond the posterior margin of the last segment of the pleon, 

 consisting of a single linear joint armed with setae. 



It is possible that the characters of the mandibular palp and 

 the terminal joints of the sixth, seventh and eighth thoracic limbs, 

 as given in the description of the type species below may be found 

 to be of generic significance when further species of the genus are 

 discovered. 



This new genus is distinguished by the combination of charac- 

 ters afforded by the unjointed antennal scale, the short entire 

 quadrangular telson and the form of the pleopods in the male. 

 It resembles the genus Potamomysis in the form of the telson, but 

 the latter genus has the antennal scale jointed and the pleopods of 

 the male quite different, the fifth pleopod reseml)ling the first, 

 second and third, and the fourth of entirely distuict form. I know 

 of no other genus with which it can be confused. Only one species, 

 the type of the genus, Indoiiiysis annandalei, is as yet known. 



Indomysis annandalei, gen. et sp. nov. 

 (Plate xii, figs. 1-5 and pi. xiii, figs. 6-13.) 



Form (fig. i) of the body moderately slender, thorax more 

 than half as long as the pleon. 



Carapace leaving the last segment of the thorax fully exposed ; 

 anterior margin not produced in the form of a rostral plate but 

 almost regularl}^ and evenly round and slightly upturned ; antero- 

 lateral corners produced into acute spiniforni projections ; a small 

 obtuse frontal spine visible below the anterior margin of the 

 carapace. 



Eyes well developed and almost completely uncovered by the 

 carapace ; form nearly cylindrical, one and a half times as long as 

 wide, cornea occupying rather less than the distal half of the eye, 

 hardly at a^l expanded, pigment black. 



Superior antenna (fig. 2) somewhat slender, proximal joint of 

 the peduncle longer than the distal two combined, the latter each 



