750 CRUSTACEA. 



base, and not angulate, of seventh pair very broad, but not as broad 

 as its length. Caudal appendages shorter than the last segment, 

 branches subequal. 



Plate 49, fig. 10 a, dorsal view, enlarged ; b, ventral ; c, leg of 

 seventh pair ; d, caudal appendage. 



Rio Janeiro, from the outside of a fish, frequently about the head, 

 and especially the upper part. 



Length, one to one and one-eighth inches. Colour, pale yellowish 

 white. Greatest breadth at articulation between fourth and fifth 

 thoracic segments. Body somewhat compressed. Form and outline 

 of head nearly semicircular. Abdomen one-third narrower at base 

 than across last segment. Branches of caudal appendages a little 

 unequal, slightly incurved, obtuse. AntennaB about seven-jointed. 

 In female, membranous plates attached to ten posterior legs, which 

 cover the whole thoracic venter ; eggs abundant under them. Liver 

 consists of two oblong masses, which extend either side of the intes- 

 tine through the three anterior segments. 



Var. compressa. — Plate 49, fig. 11 a, represents a Cymothoa, from 

 Rio, probably a variety of the preceding. The body is more narrow 

 and compressed ; the last abdominal segment has the basal angles a 

 little prominent, and is broadest at base, with the posterior side ar- 

 cuate, and breadth about twice the length; the caudal appendages 

 (fig. 11 b) extend quite to line of extremity of abdomen; the first tho- 

 racic segment projects. either side of head, almost quite to line of front, 

 and the projections are obtuse. Shell much thicker than the above. 



Cymothoa excisa, Perthy, Delect. An. Artie. Brasil. col. Spix et V. Martius, p. 211, 

 pi. 40, f. 11. 



Cymothoa frontalis ? Edwards. 

 Plate 49, fig. 12 a, dorsal view ; b, extremity of abdomen. 

 Oahu, Hawaiian Islands ; from the body of a fish. 

 Length, eight lines ; length of head, equal to its greatest breadth. 



