382 Transactions of the Society. 



resembling that now bronglit under notice. One chamber in 

 particular is entirely filled with a large sac with one tubular 

 opening which is fractured across. This sac is membranous in 

 appearance, and presents numerous minute spots which resemble 

 those already mentioned as existing upon the body in the midst of 

 Carpenteria raphidodendron. No spinules are observed, and there 

 is no room for them, but the tissue gives indications of double 

 refraction. Doubtless the tubular opening was once in relation 

 with a stolon leading to another chamber, and this form may be 

 considered as a modification of the other. A very decided calcareous 

 spicule traverses this body. 



The extraordinary shape of the organism found within Car- 

 penteria raj^hidodendron, and its curious position within a chamber 

 of a freely-growing Foraminifer, and the fact that a tubular 

 structure connects it with part of a corresponding form which 

 occupied a second and newer chamber, render this minute creature 

 very interesting. 



It may be assumed that it occupied the foraminiferal chamber 

 when there was sarcode there, for there are relics of it left ; but 

 whether the organism perforated the nummuline wall, or whether 

 this structure grew and enveloped the stolons, must be a matter 

 for conjecture. It is within our comprehension, how a siliceous 

 Sponge or a Thallophyte like Achhja penetrans Dune, can pene- 

 trate calcareous structures, but there are difficulties in the way of 

 explaining how these microscopic tubes, built up of a delicate 

 tissue containing carbonate of lime, could traverse the Foraminifer. 

 But it may be conceded that if this parasitic organism did penetrate, 

 it may have done so when the nummuline structure was a mere film. 



It may be reasonably assumed that there was a circulation 

 of water through the sacs, tube-stolons and chambers, and that 

 there was a communication with the very outside of the Foraminifer. 

 Probably the parasite nourished itself by absorption of the sarcode 

 of its host to a certain extent. 



Of the zoological position of the parasite, there may be some 

 diversity of opinion. But its calcareous tissue is not the result of 

 simple aggregation, and there is a cellular element in relation to 

 minute perforations and spinules. The small stolon openings in 

 the main sac must be remembered in relation to the whole series of 

 cavities and intermediate tubes, and the free body with its four 

 oscule-like openings is very suggestive. 



Unfortunately, except in one instance, the presence of definite 

 body spiculae is uncertain, and in that one it is possible that the 

 sac grew around the aciculate pieces of carbonate of lime. But 

 taking all things into consideration, I think that the organism is 

 a minute parasitic sponge belonging to the Calcarea. Chambers, 

 sacs, and tube-stolon growth are seen in some of the groups of 



