37 



shorter than length of carapace. Exognath of ext. ma.xil- 



lipeds i z / s times as broad as ischium Pt. polleni de Man l j 



Ext. orbital angle and anterior epibranchial tooth separated 

 by a broad sinus ; distance betw. ext. orbital angles equal 

 to length of carapace. Exognath of ext. maxillipeds 

 exactly as broad as ischium - Pi. affinis de Man 



7. Regions on carapace hardly indicated; no epigastric lobes; 



front prominent 8 



Regions on carapace (that is decidedly broader than long) 

 more or less distinct, as also the epigastric lobes ; front 

 not prominent, sinuous 9 



8. Only one tooth behincl ext. orbital angle ; carapace distinctly 



broader than long. Outer surface of palm smooth, not 

 hairy. Exognath of ext. maxillipeds scarcely broader than , 



ischium Pt. glaber Stimpson 3 ) 



Two teeth behind ext. orbital angle; carapace scarcely 

 broader than long. A brush of stiff hairs at tip of fixed 

 finger. Exognath of ext. maxillipeds twice as broad as 

 ischium Pt. riedel ii (A. Milne-Edw.) 



9. Fingers with a tuft of hairs at base of outer surface . . 10 

 No tuft of hairs on the fingers 13 



10. Surface of carapace granulate near the antero-lateral mar- 



gins; epibranchial teeth scarcely indicated; epigastric lobes 



distinct. Freshwater species Pt. pusillus Heller 



Surface of carapace punctate or smooth near the antero- 

 lateral margins 11 



1 1 . Anterior margin of front with a doublé row of granules, 



conrluent in the middle. Merus of ext. maxillipeds 



moderately auriculate, so that the greatest breadth is 



only slightly larger than the length, with the outer 



portion of the anterior margin convex; exognath i 1 /.. 



times as broad as ischium. Most likely a marine species Pt. barbatus (A. Milne-Edw.) 8 ) 

 Anterior margin of front either simple or bimarginate. 



Merus of ext. maxillipeds with a very large auricle, 



extended laterally, so that the greatest breadth much 



exceeds the length 12 



1) Pt. pusillus de Man (nee Heller), Notes Leiden Mus., v. 5, (1883) p. 161; /'/. pi'llcni de Man, Zool. Jahrb., Syst, Bd 9, 

 1S95, p. 94, Bd 10, 189S, pi. 28, f. 20. Hab. Pasandava Bay (Madagascar). 



2) See de Man, Weber's zool. Erg. Reise niedevl. Ost-Indien, Bd 2, 1892. p. 324, pi. 19, f. 11; Stimpson, Smithson. Inst., 

 Miscell. Coll., v. 49, 1907, p. 129, pi. 17, f. 5 — 5 a. Hab. Bonin Islands and Flore^. 



3) G/iat/wgtapsus barbatus A. Milne-Edwards, Nouv. Arch. Mus. Paris, t. 9, 1873, p. 316, pi. 17, f. 4: Pt. barbata Alcock, 

 1. c. p. 406; Pt. barbatus Je Man, Abhandl. Senckenb. Gesellsch., Bd 25, Heft 3, 1902, p. 505; Pt. barbata Pesta, Denkschr. Ak. Wiss. 

 Wien, Bd 88, 1913, p. 63. Widely spread, but apparently local, throughout Indo-Pacilïc region. 



87 



