124 Transactions. — Zoology. 



has several other points in common. It will be remembered 

 that A. novce-zealanclicB differs from the present species and 

 A. multiporus in the fact that the two dorsal vessels are 

 united where they perforate the intersegmental septa. 



" Nephridia. — The third and fourth segments of the body 

 are occupied by a conspicuous mass of nephridial tubules, 

 which had a pinkish colour in the specimens dissected. This 

 evidently corresponds to the ' mucus-gland ' found in the 

 other New Zealand species, A. multiporus. The nephridia 

 throughout the rest of the body are regularly arranged, one 

 pair to each segment ; the apertures do not alternate in posi- 

 tion, but are invariably placed in the neighbourhood of the 

 lateral pair of setae. There is no conspicuous muscular sac 

 forming the extremity of the tube, as in nearly all the other 

 species of the genus. The nephridia therefore are, on the 

 whole, more like those of A. novce-zealandice than of A. multi- 



2J0TUS. 



"Alimentary Tract. — The pharynx commences in the 

 second segment, and extends back as far as the end of the 

 fourth. The gizzard occupies the fifth segment. Its proper 

 position caii only be satisfactorily made out by longitudinal 

 sections, which show that the septum dividing segments v. 

 and vi. is attached to the posterior extremity of the gizzard : 

 as, however, the next septum is attached quite close to the 

 former, the growth of the gizzard has brought about an 

 increase in the capacity of that section of the body-cavity 

 belonging to the fifth segment, at the expense of segment vi. 

 Calciferous glands were entirely absent, but the oesophagus 

 was extremely vascular. The intestine is furnished with a ty- 

 phlosole which resembles that of Deinodrilus. This structure— 

 the typhlosole — has a characteristic form in, at any rate, three 

 species of AcantJiodrilus ; in the present species it is a simple 

 fold, projecting through about one-third of the lumen of the 

 intestine. In A. multiporus it has about the same relative 

 proportions, but is trifid at the extremity. In A. dissimilis 

 the typhlosole has shrunk to the most insignificant dimen- 

 sions." 



In the summary of his paper Mr. Beddard mentions the 

 following most important facts described therein : " (1.) The 

 independence of the vasa deferentia and atria in Acantlw- 

 drilus ; the two vasa deferentia of each side unite just before 

 their opening on the eighteenth segment. The atria (=' pro- 

 states') open separately upon the seventeenth and nineteenth 

 segments. (2.) The occurrence of six pairs of setas in each 

 (setigerous) somite of Deinodrilus. (3.) The completely 

 double dorsal blood-vessel of Acanthodrihis anncctens and of 

 Deinodrilus bcnhami. (4.) The enclosure of each half of the 

 dorsal vessel of Deinodrilus in a separate coelomic space." 



