98 SMITHSONIAN MISCELLANEOUS COLLECTIONS 



his C. boscii (vix Macrophthalinus hoscii x\uct. ) this character is 

 apparent, but the maxilHpeds are widely gaping, while in De Haan's 

 Cleistostoma they fit close to each other along the inner edges — a 

 character from which the name of the genus was derived. In Milne 

 Edwards's Biipla.r, which would include, according to the French 

 naturalist, the true M. hoscii, the maxillipeds are said to resemble 

 those of Macrophtliahnns, where the meros is much smaller than the 

 ischium. So that Dana's species will not strictly belong to either 

 genus, and we have ventured to arrange it, with one other before 

 undescribed, under a new generic name. 



The carapax resembles that of Biiplax, but the eyes and their pe- 

 duncles are considerably larger and thicker than in that genus. 



154. CH^NOSTOMA ORIENTALE ' Stimpson 



Cleistostoma boscii Dana, U. S. Expl. Exped., Crust., i, 313, pi. xix, fig. 3. 

 Chcenostonia orientale Stimpson, Proc. Acad. Nat. Sci. Phila., x, p. 97 

 [43]- 1858. 



This species differs from the Macrophtlialiiius boscii of Savigny 

 in the larger meros-joint of the external maxillipeds. The oblique 

 concavity on the surface of this joint is also deeper. 



It was found by us among the Loo Choo Islands. 



155. CHiENOSTOMA CRASSIMANUS" Stimpson 



Chanostoma crassimanus Stimpson, Proc. Acad. Nat. Sci. Phila., x, p. 97 

 143]. 1858. 



The following is a description of a male: Carapax quadrilateral, 

 areolated, more convex posteriorly than anteriorly. Length to 

 breadth as i : 1.31. A deep and narrow longitudinal furrow on the 

 pregastric region, bifurcating posteriorly. Surface uneven, rough 

 and hairy toward the lateral margins, but smooth and glossy near 

 the middle. Lateral margin not denticulated ; there is, however, a 

 slight emargination behind the tooth forming the angle of the orbit. 

 The eyes are large, with thick peduncles, .and reach slightly beyond 

 the extremity of the orbit. The front is broad, deflexed, and broadly 

 subtruncate below. Infraorbital margin minutely crenulated. The 

 anterior margin of the buccal area is deeply sinuous, the angles being 

 filled up by a protruding lobe, leaving a broad and deep sinus in the 

 middle, the margin of which is straight and salient ; this sinus is 



^ Eitplax boscii (Audouin). 



' Euplax crassimanus (Stimpson). 



