336 Miss H. Richardson on the Isopods of the . 



VI. EPICARIDEA. 

 Family XVI. Bopyridge *. 



Body of female primarily disciform, variously modified 

 subsequently by retrogressive metamorphosis ; distinctly 

 segmented ; more or less asymmetrical, twisted now to 

 right, now to left; dorsal face flattened; head deeply sunk 

 in thorax and carrying in front two pairs of rudimentary 

 antennae; eyes, when present, dorsal. Maxillipeds lamellar, 

 bi articulate, obtecting the oral area below, and more fre- 

 quently exhibiting a small terminal joint, and, at base, two 

 curved lanceolate appendages. Legs seven pairs, sometimes 

 obsolete on one side, and all of same structure, short, pre- 

 hensile ; coxal plates obsolete or distinctly defined. Incu- 

 batory plates, five pairs, more or less arching over the ventral 

 face of the thorax ; first pair, as a rule, concealed by second 

 and divided by a transversal fold into two segments. Abdo- 

 men more or less distinctly segmented ; pleopoda forming 

 simple or dou.ble lamella3, all of the same structure^ rarely 

 obsolete. Uropoda when present simple lanceolate. Male 

 elongate, very small, symmetrical ; segments of thorax distinct, 

 those of abdomen sometimes distinct, sometimes confluent. 

 Mouth- parts simple, conic; posterior antennae with flagellum 

 four-articulate ; legs of uniform structure ; uropoda with 

 inner branch shorter than outer. Parasitic on decapodous 

 Crustacea f. 



This family has not been sufficiently worked up to offer as 

 yet any systematic arrangement of the genera :j:. 



37. Argeia^ Dana. 



Analytical Key to the Species of Argeia. 



a. Head transverse. All the thoracic 



branchial appendages present. All 



the abdominal appendages present. . 88. A. puffettensis, T)ana. 

 a'. Head bilobate. Thoracic branchial 



appendages apparently absent in 



some of anterior segments. Last 



three pairs of abdominal appendages 



wanting 89.-4. depauperata, Stimpson, 



* Sars, ' Crustacea of Norway,' ii. 1898, pp. 195, 196, pis. xi., xii. 



t Bopyridse parasitic on Crangon crangon (Linnaeus), Neciocrangon lar 

 (Owen), Neciocrangon alaskensis, Kingsley, and other shrimps, have been 

 reserved for more detailed study. 



X See Hansen, Bull. Mus. Comp. Zool. Harvard College, xxxi. (1897) 

 p. 112. 



