GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 11 



ment of the living East Indian Lithothamnium pulchrum A. Weber 

 and Foslie. 1 



Lithothamnium fosliei (Trabucco) De Toni (Syll. Alg., vol. 4, p. 

 1761, 1905), a Miocene fossil from Italy, is figured 2 as having a 

 " coaxial " hypothallium, but from the illustrations given of the con- 

 ceptacles, there is no sufficient ground for considering this plant 

 to be a Lithothamnium rather than a Lithophyllum. In the original 

 place of publication nothing but a figure (section) is given, from 

 which, according to the scale of magnification given, it would appear 

 that the conceptacles are only 140-160 pt by 80-90 jjl and the perithallic 

 cells about 16 y. high, making the cells rather larger and the con- 

 ceptacles much smaller than in L. isthmi. 



If we are correct in including with Lithothamnium isthmi the more 

 ramified forms collected by MacDonald and Vaughan, the species, 

 though commonly coarser, appears to be sometimes suggestive of 

 plants figured as Nullipora ramosissima Reuss or Lithothamnium 

 ramosissimu?n (Reuss) Schimper, from the Tertiary " Leithakalk " 

 of the vicinity of Vienna, but Reuss's original figures and descrip- 

 tion 3 relate to external form only, and give no adequate basis for 

 referring the plant to a modern genus. Unger 4 adds good figures 

 of the vegetative structure, but shows no conceptacles. Rothpletz 5 

 describes the conceptacles of L. ramosissimum as 280 y, high, while 

 the height of the conceptacles of L. isthmi is 130-165 [x and the width 

 240-550 [x. Rothpletz has no doubt that there are two species of 

 Lithothamnieae in the " Leithakalk," which may have been confused. 



LITHOPORELLA MELOBESOIBES (Foslie) Foslie. 



Lithoporella melo'besioides (Foslie) Foslie, Kgl. Norske Vidensk. Selsk., 



1909, pi. 2, p. 50. 

 Mastopliora melobcsioiclcs Foslie, Kgl. Norske Vidensk. Selsk. Aarsber., 



1902, p. 24, 1903. 



Locality and geologic occurrence. — This species occurs in small 

 quantity with Lithothamnium isthmi in Emperador limestone of the 

 Oligocene age, " above f oraminiferous marl at Agua Salud Bridge 

 about \ mile north of New Frijoles on relocated line, Panama Rail- 

 road," D. F. MacDonald and T. W. Vaughan, 1911, Station No. 60246. 



EXPLANATION OF PLATES. 



Plate 1. 



ArchaeolWwthamnium episporum M. A. Howe. 



Photograph, natural size, of the type-specimens, collected at Point Toro, near 



Colon, Panama Canal Zone, January 10, 1910 (Howe 6832). The technical 



1 Compare pi. 4, Siboga Exped. Monog. 61. 



2 Eulithothamnium fosliei, Trab. Boll. Soc. Geol. Ital., vol. 19, pi. 11, fig. 10, 1900. 

 •Haidinger, Naturw. Abh., vol. 2, pt. 1, p. 29, pi. 3, figs. 10, 11, 1848. Type from 



" Neudorfl," Hungary. 



* Denkschr. k. Akad. Wiss. Wien, vol. 14, p. 23, pi. 5, figs. 18-22, 1858. 

 3 Zeits. Deuts. Geol. Ges., vol. 43, p. 320, 1891. 



8370°— 18h— Bull. 103 2 



