756 .T. il. ASinVORTH. 



mai'crin of tlio lamina is in many cases entire, but in some is 

 very finely dentate. The setfB of the Macquarie specimen 

 are about 5 mm. long-, and the lamina is much narrower, 

 being only about G fx in width. 



The neuropodia are well developed ; the crotchets show an 

 interesting feature. On examining the post-rostral region 

 (fig. 7), there ai'e seen to be about five to seven teeth — that is, 

 five, six, or seven teeth are in focus at the same time as the 

 rostrum, and lie approximately in the same plane. On focus- 

 sing slightly above or below this level, there comes into view 

 a number of teeth situated on the sides of the rostrum, so 

 that the latter projects from the centre of a series of teeth 

 arranged around its base (fig. 8). The small snbrostral pro- 

 cess marks the position of the base of the lowest tooth of the 

 series. Only those chjEta3 which have not been much worn 

 show these latei'al teeth.^ The rostrum is slightly longer and 

 more pointed, and the enlargement near the middle of the 

 shaft better marked than in Ehlers' species. Many of tlie 

 crotchets are strongly curved. They vary in length in the 

 Otago specimens from OGG mm. to 0*8 mm., and in the Mac- 

 quarie specimen thoy reach a length of 0"86 mm. The last- 

 named cha)ta3 are stouter, the rostrnin more rounded at the 

 tip, and more nearly in line with the shaft, and the teeth are 

 more feebly marked; these characters are due to tlie greater 

 age of tlie specimen from which the chasta? were taken. 



Musculature. — The musculature is very similar to that 

 of A. assimilis, except that the muscles in the region of the 

 first diaphragm are more slender in the Otago specimens. 

 Oblique muscles are present along the body from the first 

 diaphragm to the end of the tail. There ai-e no pouches on 

 the first diaphragm. 



Alimentary Canal. — Tlu^ aliuKMitar}' canal a-grcn^s most 

 minutely with that of A. assimilis. Multiple oc.^o])h:)geal 



' Tlicy arc very well scon in tiic crolclicts nf post-larval stages (secfi!,'. 10). 

 A similar scries of teetii is present around the base of the rostrum of tlio 

 ciirctic of oilier Arcnicolidic, but they arc not so easily distinguished as in the 

 specimens above described. 



