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4 

 6 



shape of the suborbital ridge, characters of the chelae being largel\- dependent on 

 sexual differences, and consequently only of secondary importance. 

 Key to the hido-Pacific species ') : 



1 . Two teeth behind external orbital angle, large, generally 



depressed and acute - 



Three teeth behind external orbital angle, small, conical 9 



2. Outer surface of palm with four prominent longitudinal 



j.j.ggjg D. pallipes (H. Milne-Edwards) -) 



Outer surface of palm with a single crest or smooth . 3 



3. Suborbital ridge ') with a few (2—6) tubercles, at least in cf 

 Suborbital ridge finely or coarsely serrulate or striate . 



4. Outer margins of ext. orbital angles diverging backward 

 Outer margins of ext. orbital angles converging backward; 



epigastric ridges sharp; ant. margin of front notched 

 in the middle; epibranchial teeth very acute, narrow, 

 not flattened: suborbital ridge four-lobed in cf, regu- 

 larly granular in 9. Ischium of ext. maxilliped with a 

 fine longitudinal sulcus immediately near inner margin; 

 merus nearly quadrate, with outer margin straight. 



5. Suborbital ridge notched beneath cornea of the eye, and 



thickened at either end of this notch ; a third tubercle 

 placed farther back. Palm of cheliped in cf thickly 

 clothed with hairs at inner surface and between bases 



of fingers B. penicillatus (de Haan) ') 



.Suborbital ridge with 4 low tubercles, directed forward. 

 Palm of cheliped of cf with a sharply circumscribed patch 

 of hairs at inner surface, no hairs between bases of fingers B. oregonensis (Dana)") 



B. harpax Hilgendorf *) 



1) I am unable to include B. longitaisis {Hclcrogyapstis I. Miers, I'loc. Zool. Soc. London, 1879, p. 37, pi. 2, f. 3; Ortmann, 

 Zool. Jahib., Syst., 13d 7, 1S94, p. 715) here, as the infra-orbital ridge is not described. The species is recorded from Japanese and 

 Corean waters. 



2) Pseudograpsus pallipes H. Milne-Edwards, Hist. nat. Crust., t. 2, 1837, p. 82; Helerograpsus pallipes H. Milne-Edwards, 

 Ann. Sc. Nat. (3) t. 20, 1853, p. 194; Haswei.l, Cat. -Austral. Crust., 1882, p. 100. Hab. Australia. The character of the chela here noted 

 is also observed in the 9 of ^- sexdentalus from the Mediterranean. 



3) This ridge is apparently used in the same way as in Macropht/talmus and Melapla.y^ .according to Koelbel (Wiss. Erg. 

 Keise Szichenyi in OstAsien 1877—1880, Bd 2, 1898, p. 571). the ridge produces a stridulating sound wheji being rubbed against a 

 horny crest on the inner surface of the arm of the cheliped. 



4) Silzungsber. Gesellsch. naturforsch. Freunde Berlin, 1892, n" 4, p. 38; de Man, Zool. Jahrb., Syst., Bd 9, 1895, p. 124, 

 Ud 10, 1898, pi. 29, f. 26; NoiiiLi, Ann. Sc. Nat. (9) t. 4, 1906, p. 320; Pesta, Denkschr. Ak. Wiss. Wien, Bd 88, 1912, p. 62, 

 textfig. 5. Hab. Red Sea, Atjeh and Upolu (Sanioah). 



5) Grapsiis (Eriocheir) penicillatus de Haan, Faun. Japon., 1835, P- 60, pi. 11, f. 6; Helerograpsus p. Stimpson, Proc. Ac. 

 Nat. Sc. Philadelphia, 1858, p. 104; de Man, Notes Leiden Mus., v. i, 1879, p. 71; Kingsley, Proc. Ac. Nat. Sc. Philadelphia, 18S0, 

 p. 209; Brachynolus (Helerograpsus) p. Miers, Rep. "Challenger", Brachyura, 1886, p. 264; Helerograpsus p. Ortmann. Zool. Jahrb, 

 Syst., Bd 7, 1S94, p. 714; Brachynolus p. Koelbel, Wiss. Erg. Reise Szechenyi 1877— 1880, Bd. 2, 1898, p. 570, pi. I, f. 5—6; 

 Stimi'son, Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 126. Hab. Japan and Hongkong. , 



6) Pseudograpsus oregonensis Dana, Proc. Ac. Nat. Sc. Philadelphia, 1851, p. 248; Dana, U. S. E.vpl. Exp., Crust , 1852, p. 334, 

 pi. 20, f. 6; Helerograpsus 0. Stimpson, Proc. Ac. Nat. Sc. Philadelphia, 1858, p. 104; Kincsley, Proc. Ac. Nat. Sc, Philadelphia, 1S80 

 p. 209; STI.MPSO.N, Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 126. Hab. west coast of North America. 



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