6o 



i. Euplax boscii (Audouin). 



1825. Macrophthalmus bescii (Savigny)' Audouin. Expl. planches Crust. d. 1'Egypte, pi. 2, f. 1. 



1843. Macrophthalmus boscii Krauss. Südafr. Crust., p. 40, pi. 2, f. 5. 



1852. Euplax boscii H. Milne-Edwards. Ann. Sc. Nat. (3) t. 18, p. 160. 



1852. Cleistostoma boscii Dana. U.S. Expl. Exp., Crust., p. 313, pi. 19, f. 3. 



1858. Chaenostoma oriëntale Stimpson. Proc. Ac. Nat. Sc. Philadelphia, p. 97. 



[858. Chaenostoma crassimaniis': Stimpson. Ibid. p. 97. 



1873. Euplax (Chaenostoma) boscii A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 9, p. 281. 



1880. Euplax boscii de Man. Notes Leyden Mus., v. 2, p. 71. 



18S4. Euplax boscii Miers. Zool. Voy. "Alert", Crust., p. 540. 



1886. Euplax (Chaenostoma) boscii Miers. Rep. "Challenger", Brachyura, p. 252. 



1SS8. Euplax boscii. de Man. Arch. Naturgesch., Jahrg. 53, 1., p. 357. 



1894. Euplax boscii Ortrnann. Denkschr. med.-naturw. Gesellsch. Jena, Bd 8, p. 58. 



1905. Euplax boscii Lenz. Abhandl. Senckenb. Gesellsch., Bd 27, p. 367. 



1906. Euplax (Chaenostoma) boscii Nobili. Ann. Sc. Nat., (9) t. 4, p. 319. 



1907. Chaenostoma oriëntale Stimpson, Smithson. Inst, Miscell., Coll., v. 49, p. 98. 

 1907. Chaenostoma crassimaniis'' Stimpson. Ibid. p. 98. 



1910. Euplax boscii Stebbing, Ann. S. A. Mus., v. 6, prt 4, p. 329. 



Stat. 86. Dongala, west coast of Celebes. 6 tf , 7 Q- 



Stat. 131. Karakelang, Talaut Islands. 1 <ƒ, 3 9 ( one of " tne ' atter with a parasitic Isopod in 



its left branchial cavity). 



Stat. 133. Lirung, Talaut Islands. 3 cT, 2 9 ( a 'l j uv -)- 



Stat. 225c. Luci'para Islands, Banda Sea. 2 cf , 1 9 ( aU J uv 0- 



Stat. 231. Ambon. 2 $. 



Stat. 250. Kur Island. 2 rf juv. 



On account of some discrepancy between the original descriptions of H. Milne-Edwards 

 and Dana, Stimpson founded the genus Chaenostoma tbr the reception of Dana's species, 

 which he believed to be distinct from the true "-Macrophthalmus" boscii; for this reason the 

 name Chaenostoma oriëntale was proposed. It is now generally agreed, that in reality this 

 latter is identical with Euplax boscii, for the differences in the shape of the external maxillipeds 

 are variable, so that in some specimens the merus is much more distinctly shorter than the 

 ischium than is the case in others. 



I am inclined to regard '■'Chaenostoma' crassimanus Stimpson likewise as a synonym 

 of the present species. The author does not precisely enumerate its specific characters, but in 

 comparing his description with what may be observed in adult specimens of Euplax boscii, the 

 principal differences are, that there is only a slight emargination behind the outer orbital angle, 

 ahd that the eyes outreach these angles in E. crassimanai. Stimpson's specimen is very small 

 (only 6 — 7 mm. across the carapace) and in specimens of this and of smaller size I observed 

 exactly the very differences here enumerated. It was collected, moreover, at the same locality 

 as E. boscii (Loo-Choo Islands). 



De Man (1888) remarks, that this species attains a breadth of 15 mm. across the 

 carapace, but that a 9 of only 9 mm. breadth was bearing eggs. The "Siboga"-material 



Metapla\ hirsulimana, which was afterwards by the latter author (Ree. Austral. Mus., v. 9, n» 3, 1913, p. 321), on Miss Rathbun's 

 authority, recognized to be the same as E. tridentata. The specimens were taken by the Australian authors in rather gveat quantities on 

 the mud-flats of Auckland Creek (Queensland) and of the mouth of the Paramatta River (New South Wales). 



60 



