REPOET ON THE POLYZOA. 
147 
(9) Lepralia marsupium, Macgillivray. 
Lepralia marsupium, Macgilliv., Nat. Hist. Viet., Dec. iv. p. 22, pi. xxxv. fig. 4. 
Porella marsupium, Hincks; Macgilliv., Proc. Roy. Soc. Viet., pt. 3, 1882, pi. i. fig. 2. 
1 Porella minuta, Norman. 
Schizoporella marsupium, S. 0. Ridley, Proc. Zool. Soc., 1881, p. 48. 
Character. — Zocecia ventricose, subquadrangular, deeply immersed, surface granular ; 
primary orifice arched above, with a straight or slightly sinuated lower border, in front 
of which is a pouch-like avicularium with a semicircular mandible, placed horizontally. 
Three or four articulated marginal spines above (usually detached). Ooecia (very 
numerous) globose, smooth. Operculum semi- 
circular, the lower border with two very obtuse 
angles. 
Habitat. — Station 315, lat. 51° 40' S., 
long. 57° 50' W., 12 fathoms, sand and gravel. 
[Australia, Macgillivray.] 
At first sight this form might readily be 
taken for a Porella, as in fact it is considered 
by Mr. Hincks, who also suggests that the 
Australian form is nearly related to Dr. Nor- 
man’s Lepralia minuta from Guernsey and 
Shetland. This I think is highly probable. 
But neither Mr. Hincks in his description of 
Porella marsupium (Ann. and Mag. Nat. Hist. ser. 5, vol. viii.p. 123, 1881) nor Mr. Norman 
make any mention of the oral spines noticed by Mr. Macgillivray, which are present 
in the Challenger specimen on the marginal cells. Mr. Hincks further speaks of a tooth on 
the lower margin, which I should imagine would in his system have made the species either 
a Mucronella or a Smittia, but this I think is an error into which I at first fell myself ; 
for in the Challenger specimen, the apparent tooth is in reality merely the projection 
upwards of the lower border of the median avicularium, which appears to occupy the 
same position, and to stand in the same relation to the mouth, as the median avicu- 
larium does in Eschar a foliacea and not to be within its verge as in the typical P or dice. 
In all the true Porellce, moreover, the avicularian mandible presents a minute but 
constant character (not altogether however confined to that genus), which is wanting in 
the mandible of Lepralia marsupium, viz., the existence of a curved chitinous rod on 
each side of the central foramen, as shown at a, in the accompanying woodcut (fig. 44) 
which represents the mandible of Porella compressa. The existence of oral spines is 
clearly proved by their chitinous remains as shown at h. 
Fig. 44. — Lepralia marsupium. 
a, Mandible of Porella compressa. 
b, Operculum and oral spines of Lepralia marsupium. 
