M. R. Leuckart on the Genus Notopterophorus. 355 



thoracic ring are marked with equal distinctness. The appen- 

 dages are confined to the head and thorax, as usual in the Para- 

 sita. On the former we find two pairs of antenna, and a series 

 of oral organs which, in consequence of the nearly globular 

 form of the head, follow each other at very short distances, and 

 on each segment of the thorax a pair of rather short, cleft, ven- 

 tral feet. (Krohn thinks he could count five pairs of feet, but he 

 has probably taken the organs of the mouth, which are otherwise 

 overlooked by him, as an anterior pair of feet. The figure, in fact, 

 only shows four feet.) A remarkable character is furnished by the 

 wmg-hke fohaceous processes of the dorsal see:ments, which are 

 distmguished from the analogous structures occurring elsewhere 

 m certam parasitic Crustacea by their standing nearly perpendi- 

 cular, and, by the overlapping of their lateral margins, enclosing 

 an elongated space, closed like a basket. 



In the median line of the head, at a little distance in front of 

 the anteunse, is seen a single red eye, " composed, as in Cyclops, 

 of two ocelh fused together" (Krohn). 



The two antennae (figs. 3 & 4) are short and composed of 

 only a few jomts ; the posterior (fig. 4) are hooked and furnished 

 with a claw-hke acute terminal joint. The animal is not unfre- 

 quently seen adhering to the walls of the respiratoiy cavity [of 

 the Phallusia] by means of this apparatus. Moreover, it ap- 

 pears as if the first antennae also occasionally perform the office 

 of a chnging apparatus, although the want of a terminal claw 

 and the presence of short tactile setse certainly indicate a dif- 

 ferent destination. In the anterior antennae I count seven joints, 

 m the posterior only four, which in both cases gradually dimi- 

 nish both in length and thickness towards the apex. 



The parts of the mouth are organized for biting, and not for 

 piercing; they consist, in the first place (fig. 5), of a strong 

 toothed mandible, immediately behind which, and in close con- 

 tact with it, there is a stout three-jointed appendage, which 

 must be regarded either as a palpus or as a second jaw, — the 

 latter view appearing to me to be most natural, from the archi- 

 tectonic conditions of the Parasita. The terminal joint of this 

 appendage bears a row of four long and strongly curved spines. 

 The third, or second, and last pair of jaws is represented by a 

 curved conical process (fig. 6), formed of thin, gradually diminish- 

 ing joints, and bearing on its concave surface, which is turned 

 towards the orifice of the mouth, a longitudinal series of stiff 

 bristles or spines. The spines of the last two joints are consi- 

 derably larger, but at the same time less numerous, than those 

 of the preceding basal joint. 



The legs of our Crustacean are essentially of the same struc- 

 ture on all the four thoracic segments. They consist (fig. 7) of 



24* 



