1919.J S. Kemp : Notes on Crustacea Decapoda. 337 



the unfortunate term Tympanomerus will disappear from nomen- 

 clature, for Ilyoplax has long priority. 



The species may be distinguished thus : — 



I. Eyestalk without projecting terminal style. 

 A. Carpus of cheliped without a tooth on its inner aspect. 

 [Carpus short, its upper surface about i\ times as long- 

 as broad.] 



1. Carapace pentagonal, the orbits being decidedly 



oblique; outer surface of palm granular or with 

 squamiform rugosities. 



a. Lateral border of carapace notched behind outer 

 orbital angle; male abdomen with all segments 

 distinct, distal angles of 4th segment not pro- 

 duced. 



i. Granules on outer surface of palm arranged 

 in a reticulate manner ; a strong crenulate 

 carina on outer side of both fingers ; fixed 

 finger horizontal in relation to palm ; meri 

 of walking legs with large tympana on 

 underside ' ... ••■ ■•■ T. piisitlus. 



ii. Granules on outer surface of palm not ar- 

 ranged in a reticulate manner ; no carinae 

 on outer sides of fingers ; fixed finger bent 

 downwards in relation to palm ; meri of 

 walking legs without tympana ... T. pliilippinensis. 



h. No notch on lateral border of carapace behind 

 outer orbital angles ; 4th and 5th segments of 

 male abdomen fused, distal angles of 4th seg- 

 ment produced and acute, [No carinae on 

 outer sides of fingers ; meri of walking legs 

 with conspicuous tympana] ... •■• J^- integer. 



2. Carapace quadrilateral, the orbits being almost or 



quite transverse ; outer surface of palm quite smooth 

 or with very inconspicuous microscopic granules 

 near lower border. 



a. Front narrow, less than one fifth anterior 

 breadth of carapace; a well-defined groove on 

 side-walls of carapace extending from anterior 

 angles of buccal cavern to base of penultimate 

 legs ; abdomen of male with 5th segment only a 

 little constricted, 7th broader than long. [Lower 

 surface of palm flattened and bordered by 

 carinae.] 



i. Front not more than one eleventh anterior 

 breadth of carapace; upper surface of cara- 

 pace not wider at the middle than anteriorly; 

 chela of adult male weak, similar to that 

 of female ; male with a patch of tomentum 

 on carpus and propodus of 2nd walking legs T. stevensi. 

 ii. Front not less than one seventh anterior 

 breadth of carapace; upper surface of cara- 

 pace wider at the middle than anteriorly; 

 chela of adult male strong, dissimilar to that 

 of female ; male without tomentum on 2nd 

 walking legs ... ... T.f rater. 



b. I'Vunt broader, more than one quarter anterior 



breadth of carapace; groove on side-walls of 

 carapace visible only near angles of buccal 

 cavern ; abdomen of male with 5th segment 

 deeply con.stricted, 7th at feast as long as broad, 

 i. -Anterior breadth of carapace less than li 

 times its length; front angular at sides; crest 

 defining Literal border of carapace discon- 



