GEOLOGICAL HISTORY OF THE CHAROPHYTA. 81 



fresh- and brackish- water formations up to and includ- 

 ing the Oligocene series, when it apparently became 

 extinct. No doubt the modified forms in different beds 

 represent several different species, and a number of 

 specific names have been bestowed upon them. They 

 have thick spiral-cells and the convolutions are therefore 

 relatively few. In many specimens the tips of the spiral- 

 cells are considerably swollen, which, from the analogy 

 of living species, points to their having deciduous coron- 

 ulse, and to belonging to the division Nitellese. Though 

 in size and outline they somewhat resemble the fruits 

 of Nitellopsis their structure is different. In Nitellopsis 

 the oospore belongs to the elongated type characteristic 

 of the Charese, while in the niedicaginula type the oospore 

 itself is spherical. The nearest approach to the fossil 

 fruit among living species is to be found in Tolypella 

 nidifica, Leonh. The curious organism from the 

 Wealden beds near Hastings, described and figured 

 by Prof. Seward (21) as Chara Knoivltoni, did not 

 seem to Clement Reid or myself to belong to the 

 'Charophyta. 



CAINOZOIC or TEETIAEY era. 



Eocene. — In some very restricted beds belonging to 

 the lowest Tertiary formation which are exposed in the 

 neighbourhood of Triest and in a narrow, area running 

 some distance southwards, Dr. Stache discovered a 

 large number of Charophjrte-remains. These he des- 

 cribed with excellent figures in his splendid memoir, 

 ' Die Liburnische Stufe ' (24), the name given to the 

 formation in question. In this work, and in a short 

 paper with the same title which preceded it (23), two 

 important new genera and many species were described 

 and figured. Most of the fruits figured belong to the 

 spherical type already referred to. Some of them have 

 the curious tubercular processes on the spiral-cells men- 

 tioned on p. 78. Fruits having these processes were 

 described by Lyell (11) from the Oligocene beds of the 

 Isle of Wight, and were named by him Chara tuberculata. 



vol. II. 6 



