518 



19. Maera Othonis, (M.-Edw.) 



(PI. 182, fig. 1). 



Gammarus Othonis, Milne-Edwards, Ann. Sci. Nat. Vol. XX, p. 373, PI. X, fig. 11. 9- 



Syn: Gammarus longimanus Thompson 5. 

 I — hcvis, Bruzelius. 



» Megamicra longimana, Sp. Bate 5 . 

 » — Othonis, Sp. Bate 9. 



» Msera longimana, Boeck. 



Body moderately slender and rather compressed. Cephalon fully as 

 long as the first 2 segments of mesosome combined, lateral corners angularly 

 produced, and deiined from the postantennal ones by an angular sinus. 

 Anterior pairs of coxal plates about as deep as the corresponding segments; 

 1st pair produced in front to a narrow obtusely acuminate lobe, and, like the 

 succeeding pair, having the terminal edge slightly serrate in its posterior 

 part; 4th pair somewhat smaller than the preceding ones, and simple quadran- 

 gular in form. Last pair of epimeral plates of metasome produced at the 

 lateral corners to an acuminate lobe, having below 3 deep serrations, above 

 2 smaller ones. Eyes well developed, oval reniform, pigment dark. Superior 

 antennae very slender, exceeding Vs of the length of the body, 1st joint of 

 the peduncle about the length of the cephalon, and armed at the tip posteriorly 

 with a slender spine, 2nd joint considerably longer and much narrower than 

 the 1st, 3rd joint small, scarcely 'A the length of the foi'mer, flagellum longer 

 than the peduncle, and composed of nvimerous short articulations, accessory 

 appendage twice the length of the last peduncular joint, and composed of 6 

 articulations. Inferior antennae scarcely more than half as long as the 

 superior, the last 2 joints of the peduncle about equa.l-sized, flagellum half 

 the length of the peduncle. Anterior gnathopoda rather slender, and densely 

 setous, propodos about the length of the carpus, and oblong oval in form, 

 palm very oblique and imperfectly defined. Posterior gnathopoda in female 

 somewhat stronger than the anterior, carpus slightly expanded, and terminat- 

 ing below in an angle, propodos fully as long as the 2 preceding 

 joints combined, and of a narrow oblong form, similar to that in the anterior 

 gnathopoda; those of male mitch more strongly built, with the propodos very 

 large, occupying about half the length of the leg, its form being oblong oval, 

 palm minutely serrate and imperfectly defined, dactylus strong and curved. 

 The 2 anterior pairs of pereiopoda comparatively small; the 3 posterior 

 pairs considerably larger, and having the basal joint x'ather expanded, and 



