19 



The body is soft, cylindrical in shape, and is composed of twenty- 

 two segments. The head consists of two and the thorax of eleven, 

 each of which gives attachment to a pair of branchial feet. The ab- 

 domen consists of nine, the caudal segment dividing into two broad 

 flat appendages of some length, and plumose on their edges. The 

 inferior antennae, or " cephalic horns," in the male are large organs ; 

 they are composed of two articulations, which being cylindrical and 

 curved at the apex give an appearance of a pair of horns, and they 

 have springing from near their base a filiform appendage closely re- 

 sembling in appearance the superior antennae. The structure of these 

 inferior antennae, or cephalic horns as thej' are generally termed, and 

 the filiform appendage at their base, which are frequently described 

 as an additional pair of antennae, sufficiently distinguish the genus. 



Only two species of Branchipus have as yet been described. 



1. Branchipus pisciformis, Schseifer. Antennis inferioribtis 

 maris magnis, compressis, apice bifur cutis ; appendicibus anten- 

 niformibus Jiliformibus prcelongis ; fronte prolongato, bisulco. 



Long. ^ poll. 



Syn. .Apus pisciformis, Schaeifer, Der Fisch-form. Kiefenfuss, etc. 

 t. 5!f. 1-11 (1752). 



Cancer stagnalis, Linnaeus, Syst. Nat. edit. 10. 634 (1758) ; Faun. 

 Suec. ed. 2. 497. No. 2043 (1/61) ; Fabricius, Ent. Syst. ii. 518. 

 No. 11 ; Mantiss. i. 335. No. 10; Miiller, Zool. Dan. Prodrom. 

 2351 ; O. Fabricius, Faun. Greenland. 247. No. 224. 



Branchipus pisciformis, Schaeffer, Element. Entomol. t. 29. f. 6, 7 

 (1766). 



Gammarus stagnalis, Fabricius, Syst. Entom. 419. No. 5. 



Cancer (Gammarellus) stagnalis, Herbst, Krabben und Krebse, 

 ii. 121. No. 66. t. 35. f. 8-10 (1796). 



Branchiopoda stagnalis, Lamarck, Syst. An. s. Vert. 161; Latreille, 

 Hist. Nat. Crust, iv. 319. t. 36, 37 ; Gen. Crust, i. 22 ; Bosc, Man. 

 d'Hist. Nat. Crust, ii. 234. 



Branchipus stagnalis, Latreille, Enc. Me'th. t. 336. f. 14-16 ; 

 Regne Anim. iv. 1 74 ; Leach, Diet. Sc. Nat. xiv. 542 ; Edin. Encyc. 

 vii. 384 ; Desmarest, Cons. gen. Crust. 389 ; Lamarck, Hist. An. s. 

 Vert. V. 133; M. Edwards, Hist. Nat. Crust, iii. 367; Regn. An. 

 ed. Crochart, t. 74. f. 2. 



Branchipus Schcefferi, Fischer de Waldheim, Bull. Soc. Imp. 

 Moscou, vii. (1834) ; Thompson, Zool. Research, fasc. v. t. 3. f. 1-3 

 (1834). 



Branchipus melanurusi Koch, Deutsch. Crust. H. 35. t. 2. 



Ino stagnalis 1 Oken, Lehrb. der Naturg. iii. 399. 



Larva aquatica, Linn. Faim. Suec. ed. 1. 358. No. 1357. 



Hab. In vicinitate urbis Ratisbonae ; Schceffer. In vicinitate urbis 

 Paris ; M. Edwards. 



This species according to Schaeffer' s description is half an inch 

 long, about the thickness of a straw, and semipellucid. The male is 

 generally of a pale red or flesh colour, though sometimes varying be- 

 tween vermilion and orange. The female is of a dull green, with the 



