1901.] SOME ARCTIC nemejiteans. 95 



they are sometimes scantier here, to the side of the cerebral organs, 

 where many of them open. 



Amphipoetjs lettciodus. 



Kef. Coe, W. R. Proc. Wash. Acad. Sc. 1901. 



To this species 1 have referred several small white Nemerteans 

 labelled from " Copper Island '97." The largest specimen measured 

 not more than 18 x 1*5 mm. They agree as regards their anatomy 

 fairly closely with Coe's description. Owing, however, to the 

 circumstance of their having been preserved in formalin the pro- 

 boscis armature is not present. For this reason it is impossible 

 to be absolutely certain that these specimens belong to the species 

 to which I have referred them. The excretory ducts are numerous, 

 being about 10-12 in number on either side. The posterior ones, 

 however, have not the dorsal position described by Coe (Joe. cit. 

 p. 53) for his specimens. There are 12 nerves present in the 

 proboscis. In his account of A. 1, uciodus this feature is omitted 

 by Coe. All the specimens collected by Prof. D'Arcy Thompson 

 were immature. 



Drepaxophopus borealis, n. sp. (Plate VI. figs. 4, 5, 7 ; 

 Plate YIL figs. 13-17 ; and text-figs. 2, p. 97, and 3, p. 98.) 



Several specimens obtained from Davis Strait. Even making 

 allowance for the contracted state of the specimens, this is an 

 extremely broad form compared with its length. The following 

 are the dimensions in millimetres found in two entire specimens : 



Length. Breadth. Depth. 



(1) 58 16 4 



(2) 35 10 3-5 



From this it will be seen that after preservation the breadth is 

 more than a quarter of the depth, making this the relatively 

 broadest Nemertean, with the possible exceptions of Pelar/onemertes, 

 Nectonemertes, and MalacobdeXla. 



Both anterior and posterior ends are somewhat blunted. The 

 colour and markings are characteristic. The dorsal surface is dark 

 reddish brown. Towards the tip of the head the colour is deep- 

 ened and there is a white band on either side, extending nearly to 

 the mid-dorsal line (Plate VI. tig. 7) and marking the position of 

 the head-furrows. The lateral margins of the dorsal surface, and 

 the whole of the ventral surface, are nearly white. It is some- 

 what remarkable that the coloration and markings should so 

 closely resemble those of A. thompsoni, a representative of another 

 genus from a neighbouring region. 



The epithelium is high and almost devoid of gland-cells. It 

 rests upon a Btrong basement-membrane which is considerably 

 thicker than the circular muscle-layer (Plate VI. fig. 5). The 

 relatiw thickness of the various body-layers is best seen in the 



