358 AMPUIPODA ABERRANTIA. 



next segment, armed in front with a horizontal spine. Third seg- 

 ment of the pcreion somewhat quadrate, anterior angles prominent ; 

 fourth trianguhir. Superior antenntc a little shorter than half the 

 body, very stout at the base, the first two joints being about four 

 times as thick as the following joint ; last joint of the peduncle 

 slender ; flagellum consisting of about twelve articuli, a little 

 shorter than the peduncle, articuli slightly oblong, narrow at base. 

 Inferior antennae slender, ciliato below, sparingly longer than the 

 base of the superior pair. Propodos of the first pair of gnathopoda 

 wdth a small acute prominence on the palm near the base of the 

 joint, palm hairy ; length of the propodos half that of the second 

 pair. Propodos of the second pair of gnathopoda broad and oblong, 

 narromng from the middle towards the apex, with the lower 

 posterior angle rounded ; palm nearly straight and densely hirsute, 

 without a tooth or spine where the closed daetylos reaches ; it has 

 a slender acute tooth near the middle, and an oblique, truncate, 

 subquadi-ate one just anterior. Branchial appendages nearly 

 round. First joint of the last three pairs of pereiopoda with the 

 upper apex prolonged and acute ; second joint very small ; carpus 

 stout, and having a prominence with two short spines below 

 near the base. Colour of specimens found on sea-weed nearly 

 brick-red. 

 '• Length i to frds of an inch, 



"Hah. Rio Janeiro; brought up on the anchor, Januarj-^ 1839: 

 also on sea- weed along the sea-shore beyond Praya Grande, Decem- 

 ber 21, 1838."— I>ana. 



12. Caprella robusta. (Plate LVI. fig. 10.) 

 Caprella robusta, Dana, U. S. Explor. Exped. p. 814. pi. 54. f. 4. 



" Near the C. dilatata in the horizontal beak, short cephalon, bran- 

 chiae, and other characters, but somewhat narrower. Superior 

 antennae more slender at base, a little longer than half the body ; 

 flagellum a little shorter than the peduncle. Inferior antennae 

 longer than the peduncle of the superior, ciliate below. Branchiae 

 round-eUiptic. Propodos of the second pair of gnathopoda broad ; 

 palm sparsely hirsute, bearing an acute tooth near the base, and 

 usually another small acute tooth above the middle. 



" Length about ^ an inch. 



" Hah. Rio Janeiro : from among sea-weed near the Fort, not far 

 from Praya Grande, abundant ; also brought up with the anchor in 

 the harbour." — Dana. 



Judging by the figures as well as the description, this species ap- 

 pears to be but sexually distinct from C. dilatata. 



