General History of the Marine Polyzoa. 167 
erescentic), compressed in front, where it is thickly covered 
with small punctures ; the rest of the surface smooth, usually 
an umbo on the summit. 
Loe. Zanzibar (Miss Jelly). 
Mucrone.a, Hincks. 
Mucronella diaphana, MacGillivray, form armata. 
(PI. VIII. fig. 3.) 
A form of this species occurs in New Zealand which differs 
in some respects from that described by MacGillivray, and 
most notably in being furnished with avicularia. It may 
be characterized as follows :— 
— Zoecia quincuncial, rather broadly ovate, distinct, the front 
wall somewhat flat and depressed below, rising towards the 
oral region ; surface smooth, of a delicate greyish colour ; ori- 
fice arched above, straight below, three denticles within the 
lower margin, the central one the largest, and at the top four 
long jointed spines, composed of calcareous segments, with 
chitinous joints between, articulated to a tubular base ; in the 
eentre of the lower margin a rather broad blunt mucro; at 
each side a little below the orifice (or sometimes on one side 
only) a raised avicularium, with pointed mandible directed 
outwards. Oaciwm rounded, smooth, umbonate. 
Loe. Queenscliff and Warrnambool (Mr. Watts): form 
armata, New Zealand (Miss Jelly). 
Frequently there rises immediately above the orifice a kind 
of calcareous screen, pointed above and slightly hollowed out 
in front, which is not noticed by MacGillivray. The spines, 
which are all jointed and articulated to a tubular base, are 
usually four (occasionally five) in number on the New-Zealand 
specimens ; the full complement is only met with on the mar- 
gin of the colony; on the inner cells seldom more than a single 
spine survives. 
Mucronella vultur, n. sp. (Pl. VIII. fig. 2.) 
Zowcia very large, quincuncial, sometimes rnuch elongated, 
usually ovate, convex, separated by deep sutures; front wall 
highly calcified, vitreous, surface silvery, uniformly covered 
with small circular foramina; orifice ample, suborbicular ; 
peristome slightly raised, bearing on its upper margin six 
spines, articulated to a tubular base; within the lower margin 
in the centre a hammer-shaped tooth and two small lateral 
denticles; immediately behind the central tooth a massive 
mucro, bearing on one side a large aviculariwm; mandible 
running out to a very finely-pointed extremity, which is bent 
abruptly inwards, directed upwards. Owciwm (?). 
Loc. Australia (Miss Jelly). 
