Hi; "TERRA NOVA" EXPEDITION. 



II. SYSTEMATIC AND MORPHOLOGICAL. 



ORDER METANEMERTINI. 

 FAM. AMPIIIPORID.E. 



AmpMporus, Ehrenberg, 1831. 

 I. Amphiporus moseleyi, Hubrecht. 



Ani}iliij>orns Mim'leyi, Hubrecht, 1887, pp. 20-22 ; PI. I, tigs. 20, 21 ; PI. IX, tigs. 1, 7-9 ; 

 PL X, tig. 3 :' PI. XV, figs. 11, 12, 20. 



Stations 220, 294, 339 : 45-158 fathoms. 



The collection contains three small specimens and various fragments, including 

 ] (ieces of the proboscis, which I assign to this species, not, however, without some 

 hesitation. The material being so scanty, and the specimens not attaining to the 

 large si/.e of the types in the "Challenger" collection, though some of them are 

 sexually mature, it may be questioned whether we are not here dealing with a new 

 form. But on comparing the details of the proboscis-armature, and hand-sections 

 taken through the whole animal, with the "Challenger" preparations and figures 

 of this species, the resemblances are so great, and the differences so slight, that I 

 do not feel justified in making a specific distinction. 



With so small a number of specimens at my disposal, I was unable to cut 

 a series of sections, and have therefore no important contribution to make to the 

 anatomy of the species. It may be remarked, however, that in the various trans- 

 verse sections taken by hand, chiefly in the middle or posterior region of the 

 liodv. the lateral nerve-stems do not appear to be situated quite so far dorsally 

 as in the type material. Hubrecht, indeed, lays particular emphasis on the point 

 that the nerve-stems lie ulioce the lateral gut-caeca in J. moseleyi, and notes this 

 as one of the characteristic features of the species. In the examples now under 

 consideration the nerves do, apparently, lie at some, distance from the lateral margin 

 of the body, and nearer to the dorsal than the ventral side, but they are not 

 entirely dorsal to the gut-cajca, parts of which extend outwards both above and 

 In-low them, and may be said to envelope them, as it were, on three sides. This 

 slight discrepancy may, of course, lie due merely to different states of contraction, 

 or to a difference in the level at which the sections were cut. 



The nerve-layer of the. proboscis, as \ find is the ca.se in the " Challenger 

 material, contains fourteen longitudinal nerves. 



The genital organs are also arranged as stated in Hubrecht s account. 



