NO. 6.] ACCOUNT OF THE SPECIES. 65 



brecht as Chiridius Poppei, though it is easily distinguishable, not only by 

 its much larger size, but also by several structural details. 



Description of the Female. 



The length of the largest specimens in the collection is 4'30 mm., and 

 this form accordingly grows to rather more than twice the size of the 

 Mediterranean species, the length of which is only 1'80 mm. 



The general form of the body (see figs. 1 & 2) is moderately slender, 

 with the anterior division oblong oval in form, and but slightly vaulted above 

 (see fig. 2). Seen dorsally (fig. 1), the front appears obtusely truncated; in 

 a lateral view of the animal (fig. 2), however, it is found to be narrowly 

 rounded, with no trace of any rostral projection below (see also fig. 3). The 

 cephalic and 1st pedigerous segments are completely coalesced, and the same 

 is also the case with the last 2 segments, so that the anterior division only 

 exhibits 4 distinctly-defined segments, the 1st of which is about twice the 

 length of the other 3 combined. The lateral corners of the last segment 

 gradually contract to acute, spiniform processes, which point somewhat out- 

 wards (see also fig. 4). 



The tail is rather slender, being almost half as long as the anterior 

 division, and is cylindrical in form. It is, as usual, divided into 4 segments, 

 the 1st of which, the genital segment, is somewhat shorter than the 2 suc- 

 ceeding ones combined, and forms a rounded protuberance below. The last, 

 or anal segment (see fig. 13) is much shorter than the preceding ones, and is 

 somewhat obliquely truncated at the end on each side. The caudal rami 

 are considerably longer than they are broad, are finely ciliated inside, and each 

 carry 3 strong plumose setse of about equal length. In addition to these, a 

 very short, unciliated bristle is seen at the base of the outermost seta, and 

 another, still more delicate bristle, at the inner corner. 



The eye could only be faintly traced in the alcoholic specimens. In 

 fresh specimens it is very conspicuous and of unusual size, with bright 

 red pigment. 



The anterior antennae (see figs. 1 & 2) slightly exceed in length the 

 anterior division of the body. They are very slender and attenuated, and 

 composed of 24 well-defined articulations, the 8th being, in this instance also, 



