BRANCHIOPODA. 117 



longed into a kind of rostrum, and at others forms a kind of head, 

 almost entirely occupied by a large eye. 



The first division of the Lophyropa Branchiopoda that of the 

 Carcinoida may be divided into two according to the number of 

 the eyes. 



Some of them have two. 



Here the shell completely invests the thorax; the eyes are large 

 and very distinct, and the intermediate antennae are terminated by 

 two threads. 



Zoea, Bosc. 



Very large globular eyes completely exposed, and horn-like pro- 

 jections on the thorax. 



Zoea pelagica, Bosc, Hist. Nat. Crust. II, xv, 3, 4. The 

 body semi-diaphanous; four antennae inserted under the eyes, 

 the external ones bent into an elbow and bifid; a kind of long 

 rostrum on the forepart of the thorax and between the eyes, 

 and a long pointed prominence on the posterior part of the 

 back. The feet are very short and hardly visible, the two last 

 excepted, which are elongated or terminate in a fin. The tail is 

 as long as the thorax, curved, and formed of five joints, the last 

 being large, crescent-shaped and spinous. It was discovered by 

 Bosc in the Atlantic Ocean. 



The Monoculus taurus, Slabber, Microsc. V, and the Cancer 

 germanus, L., appear to be allied to it(l). 



Nebalia, Leach. 



Triangular, flattened eyes, partly covered by a triangular and 

 arched scale. 



The feet are forked, and the terminal appendages of the tail seta- 

 ceous^). 



(1) See the Hist. Nat. des Crust, et des Insect., of Latreille, and the work of 

 Desmaresl on the Crustacea. This genus has not yet been completely described, 

 and we have not been able to procure a single specimen of it. 



(2) Nebalia Herbstii,Lea.ch, Zool. Miscell., XLV; Desmar., Consid., XL, 5; 

 Rand., Monoc. I, 8? 



The Nebalie ventrue, Risso, Journ. de Phys., Octob. 1822, probably forms a pe- 

 culiar subgenus in the section of the Schizopoda. In the Cyclops exiliens, Viviani, 

 the thorax is divided into several segments, a circumstance which excludes it from 

 the Nebaliae. It also forms a new subgenus intermediate between the preceding 

 and following one. 



N.B. A new species of this genus, the N. Geoff. Saint-Hil., lb., XV, 1, has been 

 very minutely described by Milne Edwards. The head is terminated anteriorly by 



