﻿GEOLOGY AND PALEONTOLOGY Of THE CANAL ZONE. 423 



tions on the septal margins small and serrate, not prominant. Septal 

 faces with small granulations. 



Columella very poorly developed or absent; calicinal centers as a 

 rule fairly distinct, range from 9 to 21 mm. apart. 



Thin endothecal dissepiments well developed. 



Locality and geologic occurrence. — Antigua, station 6881, Wil- 

 loughby Bay, (cotypes), and at other localities in the Antigua forma- 

 tion, Antigua, collected by T. W. Vaughan, 



Type.—^o. 325006a, U.S.N.M. 



Paratype.—Csit. No. 3250066, U.S.N.M. 



This species is closely related to the living Manidna gyrosa of the 

 Caribbean and Floridian regions. It has narrower coUines, because 

 the septa are narrow in their upper part; it has much more numerous 

 septa; and the septa of M. gyrosa have far more exsert-margins. 



The only European species, known to me, with which comparison 

 will be made is Dlplorla intermedia MicheUotti from the 011- 

 gocene of Sassello, Liguria (specimen so labelled, received from 

 the Museum of Natural History at Turin, No. 156300, U.S.N.M.). 

 This specimen, although it has the aspect of Diploria (precise synonym 

 of typical Maeandra), is in my opinion really a species of Manidna, for 

 the lower surface is corrugate and there is no epitheca, while there 

 is a complete, concentrically striate epitheca on the base Maeandra 

 {"Diploria^') lahyrinthiformis. The costae on the base of Diploria 

 intermedia are similar to those of Manidna. Besides the characters 

 already mentioned, the calicinal centers in D. intermedia are more 

 distinct than in the type-species of Diploria. I will therefore desig- 

 nate Michelotti's species Manidna intermedia (MicheUotti). This 

 species has narrower (3.5 to 7 mm. wide), shallower (2.5 to 3 mm. 

 deep), valleys, and thicker septa than M. willouglihiensis, and 

 there are distinct, thickish paliform lobes on many long septa. 

 Although the two species are distinct, the genus to which they 

 belong was coincident in the Oligocene of southern Europe and of the 

 West Indies. D'Achiardi has described two species of this genus as 

 OolpopJiijUia taramellii and C. flexuosa from the Eocene of Friuli. 



Genus THYSANUS Duncan. 



1863. Thysanus Duncan, Geol. Soc. London Quart. Journ., vol. 19, pp. 430, 439, 



pi. 15, fig8. 3a, 36, pi. 16, figs. 6a, 66. 

 1S63. Teleiophyllia Duncan, Geol. Soc. London Quart. Journ., vol. 20, p. 34. 



1864. Thysaniis Duncan, Geol. Soc. London Quart. Journ., vol. 21, p. 10. 

 1884. Thysanus Duncan, Linn. Soc. London Journ. (Zoology), vol. 18. p. 15. 

 1884. Teleiophyllia Duncan, Linn. Soc. London Journ. (Zoology), vol. 18, p. 85. 



Type-species. — Thysanus excentricus Duncan (Geol, Soc. London 

 quart. Journ., vol. 19, p. 439, pi. 16, figs. 6o, 66). 



Duncan included two species in this genus at the time he described 

 it, designating neither one as the type. Thysanus corhicula occurs 

 first in the paper, but as specimens of it are not accessible for study, 

 37149—19 -Bull. 103 16 



