some undescrihed exotic Crustacea. 187 



elongate and undilated form of the tarsal joints, and in the claws. 

 I confess my inability to allot to it its proper place among the mi- 

 nute Crustacea, the differences being in fact more conspicuous than 

 qualities by which its affinities to any one genus can be traced. It 

 was found off Port Natal, in the summer of 1835, in lat. 37° S. and 

 21° East, while I was searching for Zoea in the sea- water. It is 

 about -^th of an inch in length. 



Fig. 2. a, The animal greatly magnified. 

 b, One of the inferior antennae. 



Anofherura minutissima. Plate XX. fig. 3. 



Cyclops ecornis } Tilesius, Neue Ann. Wetterausch. i. p. 7. pi. xxi. 

 b. fig. 15. 



Dark greenish. The head very large, with two minute spines in 

 front curving downwards over the base of the superior antennae . Su- 

 perior antennae of about -j^rd of the length of the body, with two ra- 

 ther elongate joints about their middle ; the rest short, and some 

 of them spiny or hairy. Inferior antennae with the apical joint re- 

 sembling a straight claw, the preceding joint being contracted 

 posteriorly at its middle and furnished with short thick hairs. Be- 

 neath the head project two pairs of legs, the 1st with the joints 

 hairy and successively smaller until they reach the tarsus, which is 

 dilated, ovate, and furnished with a claw directed forwards. The 

 last pair of legs is much larger and longer; 1st joint short and 

 thick ; next elongate, a little contracted near its middle, and having 

 projecting from its distal head immediately in front of the articula- 

 tion a toothed spine which presents a most singular appearance ; the 

 3rd joint is also elongate, not so thick, contracted beyond its middle, 

 and spiny along the back ; the 4th is about of equal length, and car- 

 ries a set of curved spines and a claw. The 4 thoracic (?) annuli 

 are successively smaller, and furnished with bifid appendages at- 

 tached to lateral toothed plates, or processes from the rings ; and the 

 tail is composed of six joints, numerously articulated and bifid at its 

 extremity, and stands straight up at right angles to the line of di- 

 rection of the body when the animal is at rest. The body is never 

 rolled up in a ball and is quite opake. It is about V^th of an inch 

 long. It was found among marine plants. 



Fig. 3. a, The animal magnified. 



Plexocera mirabilis. Plate XX. fig. 4. 



Body and large joint of the antenna black. Head white or hyaline. 

 Eyes sessile. Antennae large, elongate, composed of 5 joints ; the 

 first two subequal, and apparently subdivided or partially subdivided ; 



