A NEW GENFS OF rOEAMINIFEEA. 455 



Affinities of the Genus. — The specimens above described were 

 discovered on two separate blocks of coral-rock. The organisms 

 appear to bare lived on the upper surface of the mass, where 

 they would be exposed to the greater circulation and excitation 

 of the water. The great abundance of specimens of Haddonia 

 may be gathered from the fact of there being 31 distinct speci- 

 mens attached to one of the pieces of rock measuring about 

 5x4 inches *. 



The genus, more than perhaps any other I have studied, 

 exhibits points of form and structure in common with several 

 other, and presumably distinct, genera. It falls naturally into 

 the arenaceous group of Foraminifera, by reason of the nature of 

 its test-structure, and appears referable to the labyrinthic group 

 of the subfamily LituoUncB. 



The valve-like aperture shows a certain resemblance, if not 

 relation, to the Clavuline and Yalvuline groups of the Texttj- 

 LAsiiDiE ; but although this detail of structure is often of great 

 use in determining the position of the organism, it must be borne 

 in mind that the characters are not always a safe criterion 

 of affinity. 



The freedom of growth and the undulating contour of Had- 

 donia also call to mind the little-known genus Sdelloidina of 

 Carter t, but that has nothing like so complicated a shell- 

 structure as Haddonia. 



With regard to the coarse porous nature of the shell-wall, it 

 has been already remarked that in this respect this genus shows 

 a similarity to Bupertia. And, indeed, on examining the dried 

 sarcode of Haddonia under a high power, sponge-spicules were 

 detected in the substance of the protoplasm, which pointed to 

 still further relationship with the group to which Bupertia 

 belongs. 



The presence of sponge-spicules in the sarcode of Polytrema 

 ^nd Carpenteria is well-known ; and on this account the latter 

 genus was at first believed by its discoverer Dr. J. E. Grray, and 

 also by Dr. Carpenter, to typify an annectant animal form 

 between the Ehizopods and the Sponges. 



Although these broken sponge-spicules are normally present 

 in the sarcode, they are sometimes found embedded in the 



* Associated with Haddonia upon the same block were other Foraminifera, 

 as 'Polytrema, Carpenteria, and Gypsina. 



■\ Ann. & Mag. Nat. Hist. ser. 4, vo]. xis. (1877) p. 201, pi. xiii.figs. 1-8. 



33* 



