SIPHONCECETES. 463 



AMPniPODA. PODOCERIDES. 



NATATORIA. 



Genus— SIPHONCECETES. 



SqjlLonwccius. Kroyer, Nat. Tidsk. i. p. 491. Voyage en Scand. pi. xx. 

 fig. 1. Spence Bate, Cat. Amph. Brit. Mus. p. 268. 

 Ann. Nat. Hist. 2 ser. xix. p. 149. Rep. Brit. Assoc, 

 1855, p. 59. White, Pop. Hist. Brit. Crust, p. 19G. 



Generic character. Superior antennae with a multi-articulate 

 flagellum, and no secondary appendage. Inferior antennae 

 having the flagellum not multi-articulate. Gnathopoda subequal, 

 subchelate. Pereiopoda short and robust. Posterior pair of 

 pleopoda very short, terminating in a single ramus tipped with 

 hooks. Telsou furnished with several rows of short, sharp 

 teeth or spines. 



The body of the animals in this genus is not laterally 

 compressed, and the coxae are very small. The eyes are 

 situated on projecting lateral lobes of the cephalon. 

 The superior antennas are shorter than the inferior, and 

 are furnished with a multi-articulate flagellum, but do 

 not carry a secondary appendage. The inferior antenna; 

 are developed nearly in the form of true legs, and 

 generally consist, we believe, of seven joints; at all 

 events the flagellum is never multi-articulate. The first 

 two pairs of legs are subchelate, and nearly alike in size, 

 the second being rather the larger. All the walking legs 

 are short and tolerably strong. The posterior pair of 

 caudal appendages terminate in a double-hooked branch. 

 The middle tail-piece consists of a single lobe, furnished 

 with numerous small teeth or spines. 



Kroyer, in his figure of the type of the genus, re- 

 presents the posterior pair of caudal appendages as 

 being double-branched, but if our observation be cor- 



