TERTIARY CALCAREOUS ALG^E. 19 



Specimen a from station No. 6856, from Friars' Hill (Oligocene), 

 Antigua, includes an apparently sterile Lithothamnium which seems 

 to be very close to Lithothamnium isthmi M. A. Howe from the Oligo- 

 cene of the Panama Canal Zone (MacDonald and Vaughan, No. 6021) 

 and may be identical with it. 



Specimen b, from station No. 6862, Hodges Bluff, lower bed (Oligo- 

 cene), Antigua, consists chiefly of one of the Lithothamnieae with rather 

 elongate subterete branches 2 to 4 mm. in diameter. In general habit 

 and in structure it seems to bear considerable resemblance to certain 

 forms of the recent Goniolithon strictum Fosl. of the West Indian region. 



A specimen from station No. 6967, top bed (upper Oligocene), 

 Crocus Bay, Anguilla, shows chiefly a millepore or other calcareous 

 animal, but incrusting it, in addition to the Lithoporella melobesioides 

 mentioned above, is a Lithothamnium that appears to be related to the 

 recent L. syntrophicum Fosl. of the West Indian region, but probably 

 differing hi having a thallus that is not always thin and crustaceous, 

 but occasionally lifted into short knobs or wartlike excrescences. 



