2 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



The fossil Lithothamnieae of Europe have been described and fig- 

 ured in considerable number and with various degrees of care and 

 detail. Most of these European descriptions and figures the writer 

 has been able to see; some of them offer a reasonable basis for the 

 future recognition of the forms concerned, without a reexamination 

 of the original materials, but many of them do not. The present 

 writer has had access to a good representation of the living Litho- 

 thamnieae of North America, the West Indies, Europe, and the East 

 Indies, but so far as the fossil forms are concerned, he has had to 

 depend upon descriptions and figures alone, which, as stated 

 above, are often very unsatisfactory. In venturing to propose as 

 new, two species of Lithothamnieae from Oligocene strata of the 

 Panama Canal Zone, he doubtless risks the possibility that some 

 future investigator, working with better materials or even with the 

 same, may be able to convince himself or even to prove conclusively, 

 that one or both of said species should be considered identical with 

 species previously described from Europe. The diagnostic charac- 

 ters, the limits of variation, and the geographic range of even the 

 living species are still very imperfectly understood. Some of the 

 species are evidently widely distributed within certain temperature 

 limits ; others are at present known from single localities. So far as 

 may be inferred from our present knowledge, very few, if any, of the 

 forms of Lithothamnieae now living in tropical America occur also 

 in European waters. 



List of Species and Theie Geologic Occurrence. 



Arehaeolithothamnnim epispomm, new species. Recent, Toro Point; and 

 Pleistocene, Mount Hope ; both in the Canal Zone. 



Lithothamnium vaughami, new species, Oligocene, Culebra formation at 

 station 6026, about half way between Monte Lirio and Bohio Ridge. 



Lithothamnium isthmi, new species, Oligocene, Emperador limestone at 

 stations 6021, about 4 miles north of Gamboa Bridge, and 6024-7), Rio 

 Agua Salud, Panama Railroad (relocated line). 



Lithoporella melobesioides (Foslie) Foslie, Oligocene, Emperador lime- 

 stone at station 6024-c, Rio Agua Salud, Panama Railroad (relocated 

 line). 



ARCHAEOLITHOTHAMNIUM * EPISPORUM, new species. 



Plates 1 to 6. 



Brownish red when living, the thallus forming at first widely ex- 

 panded crusts 0.25-1.0 mm. thick, these in many cases repeatedly 

 overgrown, the resulting crusts becoming 5 mm. or more thick, some- 

 times remaining nearly smooth or exhibiting the irregularities of the 



1 We follow Rothpletz's original spelling of the final syllable of this unfortunately long 

 name, a spelling that, happily, agreer with Phillppi's spelling of the final syllable of 

 Lithothamnium. 



