126 Rey. T. Hincks’s Contributions towards 
size, the margin frequently bearing a number of short spinous 
processes, which give it ajagged outline ; within the lower lip 
a large bluntly pointed process which stretches across on one 
side almost to the margin, and forms with it a kind of loop ; 
immediately behind this process a massive mucro, which bears 
on its inner aspect an aviculartum, with a short triangular 
mandible directed upwards; commonly on the front of the 
cell a raised avicularium, with a very long mandible, rounded 
at the apex and usually pointing downwards. Oaciwm 
rounded, shallow, smooth, often subimmersed, the opening 
closed in by a calcareous operculum. 
Loc. Off Curtis Island, on Retepora. 
This form has many points of resemblance to F. bispinosa, 
a species which is very liable to variation; but the differences 
are striking and somewhat significant, and it seems right that 
it should have aseparate name. ‘The shape of the cell can be 
observed best on the growing edge, before calcification has 
proceeded far. In an early stage it is distinctly pyriform, 
very ventricose at the upper part and depressed below; the 
surface is smooth. In later stages the surface is covered with 
a granular crust, the cells lose their distinctness, the original 
orifice is concealed by the elevation of the peristome, and a 
large opening is developed above it of somewhat irregular 
shape. The oral avicularium differs materially from that of 
R. bispinosa: in the latter it is placed transversely immedi- 
ately below the orifice, and is borne on a mound-like swelling, 
below which the mucro is situated; in the present case it 
occupies the inner aspect of the mucyro itself, which rises im- 
mediately behind the spur-like process on the inferior margin. 
The latter appendage is larger and more prominent than that 
of R. bispinosa, and of a difterent shape. Another distinctive 
feature of this species is the presence, usually in great numbers, 
of the elongate avicularia, which are somewhat elevated and 
placed on the front of the zocectum. The mandible is slightly 
expanded at the base, but throughout the greater portion of its 
length is narrow and of uniform width, terminating in a blunt 
extremity. These appendages are very conspicuous, and ‘are 
so numerous as to give a peculiar character to the zoarium 
(Pl. IV. fig. 8). The primary orifice, seems to want the 
slightly sinuated lower margin which has been noticed in\2. 
bispinosa. ‘The latter species also occurs in Bass’s Straits. 
