NOTOPLITES 339 



The frontal origin of the rootlet in this species and M. roborata is doubtless correlated 

 with the absence of any exposure of the lateral and basal walls in a bilaminar colony. 

 It is rather more pronounced in M. zelandica than in M. roborata. 



8. Menipea vectifera Harmer. Fig. 8 B. 



Menipea vectifera Harmer, 1923, p. 346, pi. xvii, fig. 23, pi. xviii, figs. 36-39. 



Station distribution. New Zealand: Sts. 929, 935. 



Geographical distribution. New Zealand (Harmer; Discovery); Palliser Bay, Wairarapa, New 

 Zealand (90.5.27.95). 



This material agrees very exactly with Harmer's description and the British Museum 

 specimens, except that in addition to the basal avicularia at the bifurcation there are 

 others of similar shape but much greater size on other parts of the basal surface (Fig. 

 8 B). These large avicularia are placed transversely and may extend across as many as 

 five series of zooecia. The figured example is not one of the largest. It seems that both 

 kinds of basal avicularia are associated with the formation by one zooecium of a pair of 

 distal buds. Where one of the inner series is duplicated in this way it invariably, as far 

 as my observations go, leads to a bifurcation and not to increase in the number of series 

 in the branch. The axillary avicularium appears to originate on the common lateral wall 

 of the two daughter zooecia and overlies parts of the basal surface of both. The number 

 of series in a branch seems to be increased solely by the marginal zooecia, the inner 

 of a pair of distal buds forming an additional inner series of symmetrical zooecia, the 

 outer bud continuing the marginal series of asymmetrical zooecia. It is at these points 

 that the large basal avicularia are found, originating from the outer of the two daughter 

 zooecia and overlying the inner of the two, and two or three more inner series. Basal 

 avicularia have not been found except in association with paired buds, but such 

 duplications do occur without formation of avicularia. 



Notoplites Harmer, 1923 



The definition of Notoplites Harmer (1923, p. 348) must be modified to admit 

 uniserial colonies with lateral branches (see N. tenuis var. uniserialis, p. 351). 



There are eight species and one variety of Notoplites in these collections, falling into 

 two groups of closely related forms: the N. antarcticus group, comprising N. antarcticus, 

 N. water si, N. drygalskii and N. vanhoffeni; and the N. elongatus group, comprising 

 N. elongatus, N. tenuis, N. klugei and N. crassiscutus. 



The four species of the N. antarcticus group all possess the internal spines noticed by 

 Waters in N. antarcticus. One projects from the proximal wall in most zooecia, and its 

 tip is divided into two or three points which may be curved and hooked (see N. dry- 

 galskii, Fig. 9 A). It is sometimes hidden in frontal view by the overlapping of the 

 proximal zooecium and the corresponding obliquity of the wall from which the spine 

 springs. N. perditus may belong to this group, see p. 355. 



In three of the four species of the N. elongatus group (N. elongatus, N. tenuis and 

 N. crassiscutus) there may be an oval, apparently thinner, area in the outer lateral wall 



