[71] 



DECAPODA FROM ALBATROSS DREDGINGS. 



415 



SERGESTID^. 



SEEaESTES AECTicus Kroyer. 



Smith, Proc. Nat. Mus., iii, p. 445, ISdl ; Bull. Mus. C'omp. Zool., x, p. 

 9G, pi. 16, fig. 4, 188-2. 



(Plate YIII, Fig. 2.) 



Sj)eciinens exam'uted. 



lu this species there is au epipod and a well-developed podobranchia 

 at the base of the first guathopod, and above its base a simple lamella 

 in place of a pleurobranchia, a large anterior pleurobranchia with a sim- 

 ple lamella back of it on each of the thrt e succeeding somites, a large an- 

 terior and a small posterior pleurobranchia on the antepenultimate som- 

 ite, and on the penultimate somite two small branchiae, of which the poste- 

 rior is very much the suuiller, while the last somite is without brauchite; 

 or, indicating the simple i)leurolamellLe by accents, branchial formula 

 mav be indicated as follows : — 



Somites. 



Epipods. 



PodobranchiiB . 

 Artlirobranchiai 

 PlourobranchisB . 



VII. 



Vm. IX. 



XVI. Total. 



(2) 



8+ (2) 



The structure of the branchiae themselves, in this and in the two fol 

 lowing species as well, is very dilferent from that in Pmanis, or any of 

 the Peuaeidse described in this paper. The branchiae are pinnate in form, 

 and each pinna is a complete i)hyllobranchia; that is. they are compound 

 phyllobranchioe, while those of Penwus are compound trichobranchioe. 

 The structure is more like that in Sicyonia (judging by Bate's descrii)tiou 

 of the branchia? of that genus) than that in Penanis. 



The first perajopods are subchelate, and the dactyli of the second gnath- 

 opods and the propodi of the first, second, and third peneopods are mul- 



