THALLOPHYTES, BRYINAE. 



opening to the outside and circular in the transverse section, leads naturally 

 to the cavity of its own sporangium. Not unfrequently with increase in 

 thickness of the calcareous rind several sporangia belonging to one whorl 

 are caked together into a broader body of the same kind inclosing several 

 cavities, each one of which is provided with its conducting canal. The 

 figures in Gumbel's 1 work illustrate these points. When calcareous cases of 

 this kind were found in the sea-sand, and their internal cavity (the sporan- 

 gium) was seen to be filled with protoplasm, it was not unnatural that they 

 should have been taken for still living Foraminifera. 



But there are many genera besides those which have now been 

 described, chiefly in Eocene, but also in Oligocene and Miocene deposits. 

 These differ much in character, in some cases so 

 essentially that their mutual relations could only 

 be thoroughly explained in a monograph. Still 

 the structure of some of them may be made in- 

 telligible with the aid of certain unimportant 

 assumptions, and be referred to the type of 

 Cymopolia. I mention as an example of these 

 Uteria Encrinella, Mich. 2 , a form common in sands 

 of the Lower Eocene formation, those for example 

 of He>ouval and Cuise la Mothe near Paris. Their 

 small members are flattened and barrel-shaped, 

 and form hollow rings bounded above and below 

 by plane surfaces rippled in radiating lines. Each 

 of these may answer to a member of the thallus, 

 in which the wall of the main axis is strongly 

 calcified, and in this respect is the opposite of 

 Cymopolia. Nothing remains of the verticillate 

 branches of the first order except the pores by 

 which their lumen communicated through the 

 calcareous deposit with the main tube. The 

 sporangia also which were not calcified and the 

 basal parts of the branches of the second order have entirely dis- 

 appeared. The outer calcareous rind of the member, pierced by honey- 

 comb-like openings, must be supposed to answer to a localised zone 

 of calcification, which was developed close beneath the rind formed 

 by the bladder-like extremities of these members of the second order. 

 The lateral walls of the branch-systems at the terminal surfaces of each 

 barrel are also calcified. From the position on the main axile tube of 

 the pores which, corresponding with the branches of the first order, mark on 

 the peripheral calcareous rind the lines of communication of these with 



FIG. 3. Uteria Encrinella, Mich. 

 B Surface-view of a member seen 

 from above, and showing the 

 lumen of the main axis as a cen- 

 tral tubular cavity, ^longitudinal 

 somewhat lateral fracture of a 

 member, showing on the wall of 

 the inner calcified tube of the 

 main axis two whorls of pores, 

 which answer to the points of 

 attachment of the lateral branch- 

 whorls. For each of these whorls 

 two whorls are seen in regular 

 order on the outer calcareous shell. 

 Each branch therefore of the first 

 order bears two whorls of the 

 second order in the median posi- 

 tion. 



1 Giimbel (1), t. n i, f. i. 



Michelin (1), p. 177 ; t. 46, f. 26. 



