422 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



MANICINA GYROSA (Ellis and Solander). 



1786. Madrepora gyrosa Ellis and Solander, Nat. Hist. Zooph., p. 163, pi. 51, 

 figs. 1, 2. 



1901. Colpophyllia gyrosa Vaughan, Geolog. Reichs-Mus. Leiden, ser. 2, vol. 



2, p. 41 (With synonymy, except Mussa fragilis Dana). 



1902. Manicina gyrosa Verrill, Conn. Acad. Arts and Sci. Trans., vol. 11, p. 85. 



1915. Manicina gyrosa Vaughan, Washington Acad. Sci. Journ., vol. 5, p. 596. 



1916. Manicina gyrosa Vaughan, Carnegie Inst. Washington Year Book, No. 14 



p. 227. 



Locality and geologic occurrence. — Canal Zone, station 5850, Pleis- 

 tocene, Mount Hope, collected by D. F. MacDonald. 



Costa Rica, station 5884&, probably Pleistocene, Moin Hill, col- 

 lected by D. F. MacDonald. 



This species is general in the elevated Pleistocene and on the living 

 coral reefs of the Caribbean area and in Florida. Usually specimens 

 are not abundant, but can nearly always be found in both the Pleis- 

 tocene and living reefs. 



There is in the Antigua formation of Antigua a very handsome 

 species of Manicina, which is of interest in showing the presence of 

 the genus in American Tertiary deposits of middle Oligocene age. 



MANICINA WILLOUGHBIENSIS, new species. 



Plate 104, figs. 2, 2 a; plate 105. 



Corallum attached by a more or less centrally placed basal peduncle, 

 from which the lower surface slopes upward and outward, upper sur- 

 face curved or flattish. Common wall thrown into rounded cor- 

 rugations, which are narrow at the lower end, but widen with out- 

 ward growth until they may be 15 mm. across, height as much as 7 

 mm. Besides the corrugations, the lower surface is costate; large, 

 low rounded costae about 1 mm. apart, with an intermediate smaller 

 costa between each pair of larger. There is no vestige of epitheca. 

 (There are only occasional shreds of epitheca on the lower surface 

 of M. gyrosa.) 



Valleys long and sinuous; from 7 to 16 mm. wide, between 10 

 and 11 mm. usual; depth 8 to 10 mm. Colline submits narrow, 

 usually from 1 to 1.5 mm. wide, but the walls of adjacent series are 

 nearly always distinct, being separated by a narrow furrow, against 

 the sides of which the outer ends of the septa terminate. 



Septa from 19 to 22 to 1 cm., one-half of which are small and 

 rudimentary; the larger septa are thin and are arranged in 2, 3, or 

 4 sizes. Near the top of the wall all septa are narrow and steep 

 through a distance of about 3 mm., below which the larger septa 

 widen by a slope of about 45°; their inner edges fall steeply, in places 

 perpendicularly, to the bottom of the axial furrow. There are no 

 definitely developed palif orm lobes, but in places the septal margins 

 rise upward just outside the steep fall into the axial fossa. Denta- 



