220 THE VOYAGE OF H.M.S. CHALLENC4ER. 



Ecto-Paeasites (PI. XXXVIII. figs. 8-14). 



All these forms belong to the Bopyridau tribe and the family Dajidas, and occur 

 attached in different parts of the anterior division of the body on certain Schizopoda 

 from the Challenger Expedition. As usual, the dwarfed males are found adhering to the 

 posterior part of the body of the much larger females. 



The form represented in fig. 8 exhibits at the first glance, both as regards its exteraal 

 appearance and relative position to the body of the Schizopod, to which it is attached, a 

 striking resemblance to the Norwegian form Aspidophryxus peltatus, G. 0. Sars. Never- 

 theless, it cannot properly be referred even to the same genus, since the clasping legs 

 are not, as in that genus, crowded together anteriorly at the sides of a very restricted 

 median area, but are found arranged along the lateral edges of the body, the four anterior 

 pairs occurring at the sides of the anterior half, whereas the posterior pair originate far 

 behind the rest, near the posterior extremity of the body. This posterior pair of legs 

 would seem, moreover, to exhibit a very peculiar structure, having the aspect of two 

 rather large posteriorly directed appendages, bifurcate at the extremity. The body is 

 distinctly segmented along the median part, and mottled there w4th densely crowded 

 pigment spots, whereas the greatly expanded and vaulted lateral parts are quite 

 smooth and jiellucid, admitting of the ovaries, with their numerous ova, to be distinctly 

 traced through their walls. The male (see fig. 8, h) is seen adhering to the posterior end 

 of the body of the female, or the rudimentary tail, and would seem to agree in structure 

 with that of Aspidophrijxus. The above recorded parasite was found on a specimen of 

 Euphamia j^elhtcida, Dana, taken off Cape Verde Islands, April 26, 1876, and was 

 mounted, together with the Schizopod itself, in Canada balsam on a glass slide. It may 

 properly be named Heterophryxus apjyendiculatus, n. gen. et sp. 



The two forms represented in figs. 9, 10, 11 would seem, as regards their general 

 structure, to agree tolerably well with the species of the genus Notophryxus, G. 0. Sars, 

 the Ijody being sac-like, with but very slightly indicated segmentation, and with the 

 five pairs of clasping legs crowded together in the anterior part of the ventral face, at 

 the sides of the oral area (see fig. 10). One of the forms (figs. 9, 10) has, however, a 

 rather anomalous position on the Schizopod, not being, as usual, attached to the dorsal 

 face but to one of the sides of the body, or, more precisely, to the base of the penultimate 

 gill, for which reason it may i)roperly be named Notophryxus lateralis, n. sj). It 

 was found on two specimens of Nematoscelis megalops, G. 0. Sars, taken in the South 

 Atlantic^ March 9, 1876. The other form (fig. 11) was found attached to the posterior 

 part of the dorsal fiice of the carapace on a specimen of Thysanoessa gregaria, G. 0. Sars, 

 taken July 10, 1875, in the North Pacific. Cwing to its comparatively short and thick- 

 set body, this form may be termed Notophryxus globularis, n. sp. 



The fourth form, finally (figs. 12, 1.3, 14), evidently belongs to the genus Dajvs. 



