NO. 1900. NEW SPECIES OF PARASITIC COPEPODS— WILSON. 239 



With the exception of the jointing of the abdomen, these differences 

 are varietal rather than specific, nor do Smith's figures add anything 

 further. But the female of phipsoni has a maxillary hook so small 

 that it was entirely overlooked by Smith, while in irritans the hook is 

 nearly as large and prominent as the second antennsB. In pMpsoni 

 the first maxillae are broadly triangular, destitute of the rudimentary 

 exopod, and do not reach the tip of the mouth tube; in irritans they 

 are abruptly narrowed .close to the base; they have a large rudimen- 

 tary exopod, and they reach far beyond the tip of the mouth tube. 



This latter is relatively very much wider in irritans, and the chitin 

 framework is altogether different in the two species. 



In the male pliipsoni the maxilliped is scarcely larger than that of 

 the female and no different; in irritans the maxilliped of the male is 

 greatly enlarged, and its basal joint is armed with two or three 

 wicked spines or catches, into which the terminal claw shuts. 



The third legs of the two species differ in size, shape, and the 

 number and arrangement of the plumose setae and spines. In 

 pliipsoni the rami of these legs are so widely separated and project 

 so Httle from the basal apron as to be invisible in dorsal \'iew; in 

 irritans they are quite prominent and much closer together. In the 

 fourth legs of the present species the three claws on the terminal 

 joint are all about the same length and a trifle shorter than those 

 at the outer corners of the second and third joints. Smith makes 

 no mention of the first maxillae, which are broad and sharp-pointed, 

 with the shape of an equilateral triangle. 



PARAPETALUS mRSUTUS (Bassett-Smith). 



Caligus hirsutus Bassett-Smith, Ann. and Mag. Nat. Hist., eer. 7, vol. 1, p. 6, 

 pi. 3, figs. 1 and 2. 



Plate 33, figs. 28 to 35. 



Both sexes of this species were found in the gill cavity of Polyne- 

 mus tetradactylus at Bombay, India, by Bassett-Smith and were 

 described by him as a new species of Caligus. But they belong to 

 the genus Parapetalus rather than Caligus for the following reasons: 

 1. The genital segment is prolonged at the posterior corners into a 

 broad, two-lobed wing, and the sides of the abdomen also are flat- 

 tened into broad wings. 2. The grooving of the carapace is different 

 from that found in Caligus, or in any of the Caliginse, and resembles 

 much more that in the Euryphorinje. 3. The fourth legs are short 

 and tliickset, and the three terminal joints are sohdly fused and 

 armed with winged spines. 4. The egg strings are long and thread- 

 like, similar to those of Lernanihropus, and not at all like the com- 

 paratively plump strings of Caligus and LepeopTitheirus. 



Besides locating his specimens in tlie wrong genus, Smith made 

 several blunders in describing them. Of tlie female he states ''Cepli- 

 alothorax oval, nearly twice as long as broad, about one-tliird the 



