A: it’s a Phaeodaria, family Coelodendridae. Probably Coelechinus or Coelodiceras.
B: Strange. Is it spherical? If so, some acantharian cysts have a surface similar to the one here. Try to break it and see what’s inside (Ac. cysts usually have the spiny bug inside)
C: Looks like an Aulacanthidae (Phaeodaria), probably Aulacantha. Take a close look at the spines, should be loose inside the protoplasm and the shape of the tips should help to tell the genus.
D: don’t know.

Demetrio Boltovskoy (2004/10/11)

B is a sphere, C is a flat disc and D comes in many sizes, this was one of the smaller ones (background grin is 1mm squares). It was suggested that I could use an acid digestion to remove debris form the spines, does that work? I will break open a B to see if there is anything inside. Thanks

Moira Galbraith (2004/10/11)

A. The information provided by the photo is incomplete for a precise determination. We do not know if the spines are hollow or massive. If they are hollow the specimen is a phaeodarian and could belong to the family Coelodendridae as Demetrio supposed. If not, it is a spumellarian. If the specimen were a phaeodarian we should have seen the phaeodium because it seems that the specimen was alive when it was collected. And I see no phaeodium and no bivalved shell. Also, the type of spine branching is not characteristic of the Coelodendridae. In my opinion this specimen is a spumellarian belonging to the family Thalassothamnidae, that comprises large-sized spicular radiolarians. It is probably a species of Thalsssothamnus because of its non-branched central capsule. If the central capsule were branched the specimen would have belonged to Cytocladus Schroeder. It seems that one can even see in the figure that the spines originate in a centre, which is characteristic of this family.

B seems to be the planktonic foraminifer Orbulina universa. The large pores and the pustulate surface is characteristic of this species. Unfortunately we do not know the diameter of the specimen. The size of O. univera is up to 0.7-0.8 mm.

For figure C I agree with Demetrio: it is Aulacantha, quite probably A. scolymantha on the basis of its simple spines.

Figure D seems to be Oroscena regalis Borgert translated by Friend and Riedel (1967) to Orodendrum.

Paulian Dumitrica (2004/10/18)

Orbulina universa, whole specimens (left, center) and detail of wall (right). Scale bars are 50 microns.

Although it does indeed look very much like Orbulina universa, I am hesitant about the identity of B because O. universa should have a perforated shell (see pictures), and there don’t seem to be any pores in B, just small bumps, pustules. Besides, the spherical shell of O. universa is supposed to have the coiled foraminifer inside (see figure), whereas the one shown in B, as Mora informed me, is empty.

Demetrio Boltovskoy (2004/10/20)

I do not agree with Demetrio. The larger black circles of B are pores in my opinion. And the first image Demetrio gives of O. universa shows clear that B and O. universa are similar. As a reply to the remark of Demetrio that O. universa has coiled inside I have to say that usually there is nothing inside the outer sphere of this foraminifer, the internal chambers are usually missing, dissolved even during the life of this species probably. After I read Demetrio's remark I crushed several tens of specimens of O. universa from the Quaternary of the Mediterranean Sea and I found no shells inside. So for the moment I remain of the idea that B is Orbulina universa.

Paulian Dumitrica (2004/10/21)