1900.] POT-TNOID FROM XEW ZEALAND. 979 



close together that at first sight a single pair only appears to 

 exist, but its anterior limit is not distinctly marked, as it is 

 produced into the cylindrical bases of the three tentacles \ The 

 length up to the base of the median tentacle is about equal to the 

 breadth (2| mm. by 2| mm.). The median tentacle is slightly 

 longer than the lateral, and its base is depressed very slightly 

 below those of the lateral pair, which thus form a shallow V-shaped 

 groove behind it. The median tentacle is about 6 mm. long; the 

 lateral pair being 5 mm. each, measured to the posterior end of 

 the base. Arising between the prostomium and peristomium, on 

 the lower surface of the head, is a pair of palps about 9 mm. long, 

 which just below the tip narrow suddenly to a fine point ; they 

 bear 7 to 9 longitudinal rows of papilla?, which take a somewhal 

 spiral course. 



The peristomium bears a pair of considerably modified parapodia. 

 Each consists of a conical base bearing two cirri, a dorsal and 

 a ventral, which resemble the tentacles (Plate LXI. fig. 4). On 

 the anterior dorsal surface of the base a very small bunch of hair- 

 like bristles protrudes, corresponding 1o the notopodial hairs of 

 succeeding segments. 



On the ventral surface of the head the mouth has been already 

 sufficiently described ; only one point remains to be noticed, 

 namely, that the ventral cirri of the second segment are elongated 

 and bulbous below the tip, just like the preceding pair. They are 

 generally inclined towards the mouth, and are termed the buccal 

 cirri. In some specimens the ventral cirri of the next segment 

 showed a tendency to swell below the tip, more marked than in 

 those further back (Plate LX. fig. 2). 



Eli/tra. — A reference to fig. 1 will give a better idea of the 

 arrangement of the elytra than any description. They are 

 attached to the body by a considerable area, the " areola," of an 

 oblong form and of considerable breadth. The corresponding area 

 ou the body is the elytrophoiv (Plate LX. fig. 3), and lies obliquely 

 transverse on the flattened parapodial ridge mentioned above. 

 The colour of a typical elytron is a warm brown behind a line taken 

 transversely across about its middle, the colour advancing forwards 

 somewhat at the inner end (indicated by dots in Plate LXII. fig. 10). 

 The part covered by the preceding elytron is light buff, and this 

 colour extends backwards over the anterior slope of the areolar 

 ridge. 



The elytra vary considerably in size and shape according to 

 their position, the terminal ones being smaller. Plate LXII. 



1 In Lepidonotus it is usually stated that the " prostomium is produced into 

 the base of the lateral tentacles " ; as a matter of description this is true, but, 

 from the comparative anatomy of the group, it appears that the cylindrical 

 " prolongation " (marked b.t. in the figure) should be regarded as the base of 

 the tentacle fused with the anterior margin of the prostomium : this margin is 

 in the present annelid just indicated by a faintly marked, oblique line ; and if 

 this be compared with the prostomium of Harmothoc and others, this interpre- 

 tation seems reasonable. — W. B. B. 



Proc. Zool. Soc— 1900, No. LXIV. 64 



