REPOET OX THE FORAMIHIFERA. 
719 
species from some of the wild-growing Planorbulince, such as Planorbulina acervalis and 
Planorbulinci retinaculata} 
Schultze’s figure of Acervulina inhcerens represents a specimen consisting of a few 
large, coarsely perforated, convex, adherent chambers, which when living and filled with 
sarcode were of a pink hue. Although hitherto overlooked, there can be no doubt that, 
the organism referred to pertains to the species under discussion, and precedence must 
therefore be given to the specific name under which it was described. 
Gypsina inhcerens is a tolerably common shallow- water Foraminifer. It was only 
collected at two Challenger Stations : — off East Moncoeur Island, Bass Strait, 38 fathoms ; 
and off Booby Island, south of New Guinea, 6 fathoms ; but it is a familiar object at 
many points on the European coast-line. 
There appears to be no record of its occurrence as a fossil. 
Polytrema, Risso. 
Millepora, pars, Linne [1788], Esper, Lamarck. 
Polytrema, Risso [1826], Blainville, Dujardin, Jones and Parker, Morris and Quekett, Carpenter, 
Schultze, Allman, Horrnan, Carter, Brady, Moebius. 
Pustularia, Gray [1858]. 
The little red parasitic organism, familiar under the name Polytrema miniaceum, has 
a peculiar interest, not only on account of its striking external resemblance to certain 
corals, but from its morphological relations with some allied types of Foraminifera. It 
was naturally regarded by the earlier writers as a “ Zoophyte,” and invariably classed by 
them either amongst Corals or Polyzoa. Its true zoological character and position were first 
determined by the French naturalist Dujardin, about the year 1841 ; and since that 
time the structural features of the test, as well as the nature of the animal inhabiting it, 
have been more or less minutely studied by Carpenter, Schultze, Allman*', Carter, and 
Moebius. 
The test of Polytrema is adherent, and in its typical aspect has the form of an 
irregularly convex tuberculated or arborescent mass, somewhat spreading at the base ; 
with conspicuous orifices on its free surface, which are often situated in papillse or 
in elongated simple or branched tubes. The exterior is areolated in various ways, and 
the colour of the shell is generally some shade of red. The internal structure bears 
considerable analogy to that of Gypsina , the test being composed of a multitude 
of small chambers, arranged spirally just at the commencement, but subsequently in more 
or less regular layers. The subdivision into chambers, however, is seldom quite complete 
or uniform ; and in arborescent specimens the centre of the branches is occupied by 
1 Parker and Jones state that “ on Chama gigas there is often a wild-growing parasitic Tinoporus isomorphous with 
Planorbulina retinaculata, but still larger,” Phil. Trans., vol. civ. p. 381 ; — probably the present species. 
