VIl] CONFER VOIDEAE. 177 



examples of Ooniolina suggest a comparison with Echinoid 

 spines, but the resemblance which many of the forms in the 

 Sorbonne collection present to large calcareous Siphoneae is 

 still more striking. A comparison of Saporta's fig. 5, PI. xxxiii. 

 and fig. 4, PI. xxxii. in volume iv. of the Flore Jurassique, with 

 the figures given by Solms-Laubach' and Cramer" of species 

 of Bornetella brings out a close similarity between GomoKwa 

 and recent algae ; the chief difference being the greater size of 

 the fossil forms. The possibility of confounding Echinoid 

 spines with calcareous Siphoneae is illustrated by Rothpletz', 

 who has expressed the opinion that Gumbel's Haploporella 

 fasciculata is not an alga but the spine of a sea-urchin. 



Among Cretaceous forms, in addition to Ooniolina, which 

 passes upwards from Jurassic rocks, Triploporella* and other 

 genera have been recorded. 



Uteria^ is an interesting type of Tertiary genera; it occurs 

 in the form of barrel-shaped rings, which are probably the 

 detached segments of a form in which the central axial cell 

 was encrusted with carbonate of lime, but the sporangia and 

 the whorls of branches differed from those of Gymopolia in 

 being without a calcareous investment. 



6. CONFERVOIDEAE. 



Without attempting to describe at length the fossil forms 

 referred to this division of the Chlorophyceae, there is one fossil 

 which deserves a passing notice. Brongniart in 1828" instituted 

 the generic term Gonfervites for filamentous fossils resembling 

 recent species of confervoid algae. Numerous fossils have 

 been referred to this genus by different authors, but they 

 are for the most part valueless and need not be further 

 considered. In 1887 Bornemann described some new forms 

 which he referred to this genus from the Cambrian rocks of 

 Sardinia. He describes the red marble of San Pietra, near 



1 Solms-Laubaoli (93), PI. ix. figs. 1, 8. = Cramer (90). 



3 Eothpletz (922) p. 235. * Steinmann (80). 



= Solms-Laubaoh (91), p. 40. fig. 8. Vide also Deeoke (83) PI. i, fig. 12. 

 « Brongniart (28) p. 211. 



S. 12 



