222 THE VOYAGE OF H.M.S. CHALLENGER. 



Echinorhynckus, Miiller, more especiiiUy by the cylindrical proboscis (see fig. 17), pro- 

 truding from the ventral face of the anterior extremity, and armed with numerous 

 strongly chitinised recurved hooks (fig. 18). The body (see fig. 16) is rather elongate 

 and somewhat flattened, irregularly wrinkled transversely, and o1:)tusely rounded at 

 both ends. It was found within the body cavity of a specimen of Exiphausia j^ellucida, 

 Dana, occupying the greater part of its length, and bent, moreover, in the form of the 

 letter S (fig. 15). The species may, on account of its irregularly wrinkled body, be 

 properly named Echinorhynchus corrugatus, n. sp. 



The other form (figs. 19-23) exhibits a very peculiar appearance, but may neverthe- 

 less be undoubtedly determined as a species of the genus Distomum, Zed., since it 

 presents two well-defined sucking disks, the one anterior, or oral, the other ventral. The 

 body is not, as usual, flattened, but cylindrical and twisted in a peculiar manner, having, 

 moreover, the ventral sucking disk mounted at the end of a cylindrical peduncle that 

 stands out at right angles from the body. The integument is rather firm and muscular, 

 as also densely wrinkled transversely throughout its anterior half, but rather pellucid, so 

 as to admit of the two spirally twisted intestinal caeca being distinctly traced within the 

 body. The most peculiar feature of this form is, however, the mode in which it is 

 aflixed within the body cavity of the Schizopod. For this is not efi'ected by any of the 

 sucking disks, but with the aid of a kind of byssus excreted from the posterior end of 

 the animal and dispersed within a peculiar sac-like body, lying transversely within the 

 posterior part of the body cavity of the Schizopod (see fig. 19), and at least with one of 

 its extremities firmly connected with the outer skin, thus often producing a conspicuous 

 mamiUiform projection behind the posterior gill (see PL XXIII. fig. 10). Whether this 

 peculiar body ought to be referred to the parasite itself, or possibly should be regarded 

 as a pathological product of the Schizopod, is still uncertain. On opening the body just 

 mentioned, the byssus is found toconsist of two rather strong filaments (see figs. 21, 22), 

 more or less twisted upon themselves, as a rope, and of a number of very fine and 

 highly adhesive fibres (fig. 23), partly curled up in globular masses, and partly stretching 

 along the two filaments. The slightest touching of the byssus with any object will 

 cause such objects to adhere rather firmly thereto, even in spirit-specimens. This 

 very peculiar intestinal worm I found in several specimens of the two Euphausiidans, 

 Neviatoscelis megcdops, G. 0. Sars, and Thysanocssa gj-egaria, G. 0. Sars, from the 

 South Atlantic, invariably aflixed within the body cavity of the Schizopod in the same 

 peculiar manner, the body itself with its sucking disks being freely suspended anteriorly 

 within the perivisceral fluid, and, as a rule, a little asymmetrically, towards the right or 

 left side of the intestinal canal of the Schizopod. Professor Leuckart has proposed to 

 designate the species Distomum filiferum, n. sp., and will give a short account of its 

 structure in an Appendix to one of the forthcoming Zoological Reports. 



