a General History of the Marine Polyzoa. 123 
and seems to have been little noticed since his time. Its 
remarkable peculiarity is the line of spines fringing the base 
of the cell for about half its length. It is not uncommon in 
Capt. Warren’s dredgings, on shells, Retepores, &c. 
PoRELLA, Gray. 
Porella marsupium, MacGillivray. 
(PI. I. fig. 6.) 
This species is nearly related to the British P. minuta, 
Norman. MacGillivray does not notice the tooth on the lower 
margin, which is sufficiently conspicuous ; nor does he describe 
the shape of the orifice; but, on the whole, there is ground, 
I think, for identifying the form which I have figured with 
his species. ‘The whole surface is sometimes punctured; in 
other cases there is only a row of perforations round the edge. 
Loc. Bass’s Straits, on shells &c., extremely common in 
the dredgings. 
7 Smirria, Hincks. 
Smittia Landsborovii, Johnston, var. purpurea. 
This differs from the English form in colour, being com- 
monly of a rich purple. It exhibits another peculiarity which 
I have not met with before in this species: the ocecium is 
“ hooded ;”’ and in the fertile cell the peristome gives off two 
processes in front, which meet across the orifice, leaving a 
circular opening, through which the avicularium is visible *. 
These, however, are merely varietal differences. 
Smitiia reticulata, J. MacGillivray, var. 
The aviculariwm always placed on one side of the sinus, 
close to the peristome, directed downwards, elongate (some- 
times of great length) ; the mandible of much the same width 
throughout, rounded at the extremity. 
In all essential characters this form agrees with the normal 
S. reticulata ; but the avicularium is modified in shape, and 
is constantly placed in a different position. In the usual 
form it is situated centrally immediately below the sinus, and 
is furnished with an acute mandible. Though the variation 
is comparatively trifling, it affects very materially the appear- 
ance of the species. 
The normal form also occurs. 
* As in Microporella ciliata, vax. personata. 
