386 



PART II. SYSTEMATIC ACCOUNT 



В 



part of the spermatophore (Fig. F152£). The length of the spermatophore 

 is 0-3 mm and the greatest width 0-075 mm. The filament is extraordinarily 

 long and thin. 



The brown elastic thin-walled tube is segmented and ringed. Its surface 

 is lustrous. The segments are noticeable only in the anterior part of the 



tube and each contains, as a rule, five 

 rings (Fig. G152A), but it is not rare 

 to come across segments with four, 

 six or even seven rings. The first and 

 last rings in a segment are usually 

 longer and a little darker than the 

 others. The anterior part of the tube 

 is flimsy and transparent. The rings 

 are brown, regular, homogeneous and 

 transparent, and their length is usually 

 a third to a half the diameter of the 

 tube, but occasionally almost equal to 

 it. The interspaces between the rings 

 are clear and transparent. The seg- 

 ments gradually disappear and the 

 greater part of the tube is charac- 

 terized by noticeably shorter rings 

 (Fig. G1525). In the hind part of the 

 tube they become muddy brown, 

 opaque and somewhat fibrous, with 

 darker edges (Fig. G152C). Still nearer 

 the end the distance between the rings 

 becomes greater and the rings them- 

 selves become irregular with crooked 

 edges (Fig. G152D). In the hindmost 

 part of the tube the rings gradually 

 fade and ultimately disappear. The 

 tube is up to 140 mm long and the 

 anterior diameter 0-2-0-3 mm. 



D. southwardae is distinguished from 



other species of this genus by its 



large size, which is possibly connected with the increase in number of the 



tentacles to three or even four. The chief distinctions of this species, however, 



appear to be the very small size of the cephalic lobe and its lappet-like shape, 



0.2 



MM 



Fig. G152. Diplobrachia southwardae: A-D - 

 successive parts of the tube. 



