ISOPODS OF NORTH AMERICA. 237 



The first three pairs of legs are more or less manifestly shorter than 

 the others. Ungulae subequal. 



Male is much smaller in size than female. 



ANALYTICAL KEY TO THE SPECIES OP THE GENUS MEINERTIA. 



a. First pair of antenna? short, extending to the eye or to the posterior margin of the 

 head. Second pair of antennae short, extending to the posterior margin of the 

 head, and composed of only eight or nine articles. Head more or less deeply 

 set in first thoracic segment. 



b. High carina present on the basis of the last four pairs of legs. Uropoda extend 

 beyond the terminal abdominal segment. Eyes small. Last segment of 

 abdomen about twice as wide as long. 



c. Body convex. Terminal abdominal segment trapezoidal and rugose dorsally. 



Meinertia gaudichaudii (Milne Edwards) 

 (/. Body flattened from fourth segment to end of abdomen. Terminal segment 



semicircular and smooth dorsally Meinertia deplanata ( Bovallius) 



V . No carina developed on the basis of the legs. Uropoda extend only a little 

 beyond half the length of the abdomen. Eyes large. Last segment of abdo- 

 men nearly three times as w 7 ide as long Meinertia gilberti Richardson 



a'. First pair of antennae long, extending to the middle of the first thoracic segment. 

 Second pair of antennae long, extending to the posterior margin of the first 

 thoracic segment, and composed of fourteen articles. Head but little immersed 

 in first thoracic segment Meinertia transversa Richardson 



MEINERTIA GAUDICHAUDII (Milne Edwards). 



Cymothoa gaudichaudii MILNE EDWARDS, Hist. Nat. Crust., Ill, 1840, p. 271, 



Ceratothoa rapax HELLER, Reise Novara, Crust., 1865, p. 146, fig. 17. 



Ceratothoa gaudichaudii SCHIOZDTE and MEINEKT, Naturhistorisk Tidsskrift (3), 



XIII, 1881-83, pp. 335-340, pi. xin, figs. 11-15. 

 Meinertia gaudichaudii STEBBING, Hist, of Crust., 1893, p. 345. RICHARDSON, 



Proc. U. S. Nat. Mus., XXI, 1899, p. 829; Ann. Mag. Nat. Hist. (7), IV, 



1899, p. 171; Proc. Wash. Acad. Sci., Ill, 1901, p. 568. STEBBING, Willey's 



Zool. Results, 1902, p. 643. 



Localities. Mazatlan; Pacific Ocean following the shores of Central 

 America; Coquimbo; shores of Chili; Callao; Peruvian shores; Chin- 

 chenses Islands; Black Bight, Albemarle Island, Galapagos Islands; 

 200 miles north of Wenman Island, Galapagos Islands; Panaieti, 

 Louisiade Archipelago, New Guinea. 



Found in the mouth of Thunnus sp. 



Body elongate, nearly three times as long as broad; 16 mm. : 45 mm. 



Head nearly twice as wide as long (4 mm.: 7 mm.) somewhat tri- 

 angular in shape, with apex obtuse. The head is deeply set in the 

 first thoracic segment, the narrow and acute antero-lateral angles of 

 which extend half the length of the head. Ej^es small, distinct, irreg- 

 ular in outline, but inclined to be square, and placed at the sides of 

 the head, a little below the middle. 



The first pair of antennas are composed of seven articles, the two 

 first ones being almost fused; they extend just below the eye. The 

 second pair of antennae are composed of nine articles and extend to 



