2G4 JOURNAL, BOMBA Y NA TURAL HISTORY SOCIETY, Vol. XII. 



caudal segment with eight keels ; tail about five times the length of the 

 carapace, slender ; the 1st segment a little longer than wide ; 4th 

 segment, more than twice as long as wide, as wide as the brachium. 

 Palpi with hand granularlj crested above, denticulate internally, its 

 width a little greater than that of the brachium and nearly two-thirds as 

 long as the hand-back; hand-back three-quarters the length of the 

 movable digit, which is armed with six rows of teeth, the external 

 series consisting of seven, 



Pectinal teeth 12. 



Measurements in viilUmetres. — Total length 42, of carapace ■J, of 

 tail 23-5. 



Zoca^%. — Mangalore (Battie)^ and Kanara (T. R, D. Bell). 



This species is related to Isometrus hasilkus, described by Karsch, 

 from Ceylon, of which the British Museum possesses male and female 

 examples obtained by Mr. E. E. Green at Haldumullah in this island. 



The resemblance lies in the form of the vesicle and aculeus of the 

 tail, size of hand, pectinal teeth, etc., but this new form differs in 

 being more strongly granular with a narrower tail, etc. ; the colouring 

 also is different, the palpi in /. hasUicus being much more s])otted with 

 black, while the upper side of the trunk and legs are much more 

 noticeably spotted with yellow ; the tail too is yellow and spotted, and 

 blotched throughout with bkck. 



Isometrus acanthurus, sp. n. 



Colour variegated yellow and black ; carapace lined with black, its 

 anteocular area infuscate, spotted with yellow ; tergal plates ornamented 

 with fine black lines separated by yellow patches ; 4th and 5th 

 sternal plates lined with black ; tail mostly yellow, delicately lined with 

 black ; the 5th segment blacker posteriorly ; vesicle also lined with 

 black; legs and palpi spotted ; hand slightly spotted externally ; fingers 

 pale, spotted externally. 



Trunk and tail finely granular ; terga with a median keel ; sterna 

 smooth, the 4th laterally granular, the 5th granular throughout, 

 with four keels. Tall long and slender, about seven times the length 

 of the carapace ; the 2nd segment with only eight keels ; terminal 

 granule of superior keels on 2nd and 3rd segments long, erect, and 

 spinifonn ; vesicle elongate, granularly crested below ; the aculeus short 

 strongly curved ; spine triangular, but with blunt apex. 



