gig CRUSTACEA. 



Caprella cornuta. 



Corpus gracile, segmentis oblongis, 2do thoracis, 3tio, 4fo, btoque inter se 

 longitudine subcequis. Caput aculeo arrecto prope dorsum medium 

 armatum, segmento proximo interdum dimidio brevius. Segmentum 

 tJwracis 2dum non triplo longius quam latum. Antennae \mae dimidio 

 corporis paulo longiores, sat graciles, flagello 10-14:-articulato, itd 

 parte breviore quam basis. Antemwe 2dee basi superiorum vix lon- 

 giores aut breviores. Branchial anguste elliptical. Manus lmaparva, 

 secunda oblonga, duplo longior, palmd rectiusculd dente sub-basali et 

 altero ante medium acutis armatd. 



Body slender, segments oblong, second, third, fourth, and fifth of 

 thorax subequal in length. Head hardly higher than long, a little 

 shorter than next segment, armed near middle of dorsal surface 

 with an acute spine, obliquely erect. Second thoracic segment not 

 three times as long as broad. Superior antennae rather longer than 

 half the body, moderately stout ; flagellum ten to fourteen-jointed, 

 one-fourth shorter than base. Inferior antennae very little longer or 

 slightly shorter than base of superior. Branchiae narrow elliptic. 

 Hand of first pair small ; hand of second pair oblong ; palm nearly 

 straight, having an acute tooth on palm near base, and another 

 anterior to middle. 



Plate 54, fig. 5 a, b, views, enlarged ; c, part of flagellum of supe- 

 rior antennae ; d, third thoracic segment ; e, hand of first pair ; /, ibid, 

 of second pair ; g, extremity of leg of last pair. 



From among sea-weed near the fort, not far from Praya Grande, 

 Rio Janeiro. December, 1838 ; both males and females were abun- 

 dant. 



Length, about one-half an inch. Colour, dull yellowish, reddish. 

 The acute spine on the head is situated near middle of dorsal surface. 

 The flagellum of the superior antennae had but ten joints ; but the 

 first joint was oblong, and seemed to consist of three or four joints 

 united; the last two joints of the inferior antennae are together as 

 long as preceding one ; the joints are oblong, more than twice as long 



