440 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



3. SIDERASTREA STELLATA Verrill. 



Plate 115, figs. 2, 2a, 26. 



1868. Siderastraea stellata Verrill, Conn. Acad. Arts and Sci. Trans., vol. 1, p. 352. 



1901. Siderastrea stellata Vatjghan, Geolog. Reichs. Mus. Leiden Samml., ser. 2, 



vol. 2, p. 62. 



1902. Siderastraea stellata Verrill, Conn. Acad. Arts and Sci. Trans., vol. ll r 

 p. 155, pi. 30, figs. 4, 5. 



This species resembles 8. radians in usually having the fourth 

 cycle of septa incomplete, in the flattened outer margins and very 

 steep inner margins of the septa, and a deep columellar fossa. It 

 differs, as a comparison of thefigures shows, by having deeper calices, 

 which may be meandriform, by its more coarsely dentate septa, and 

 by its much less developed, finely papillate columella. It is a very 

 distinct species and is not a synonym of S. siderea, as Gregory sup- 

 posed. 1 The specimen figured (pi. 115, figs. 2, 2a, 2b) is No. 36859, 

 U.S.N.M. 



Locality and geologic occurrence. — "It is widely distributed on the 

 coast of Brazil; Bahia, Abrolhos reefs, etc.; " living. 2 



4. SIDERASTREA CONFUSA (Duncan). 



1867. Isastraea confusa Duncan, Geol. Soc. London Quart. Journ., vol. 24, pp. 

 14, 24, pi. 2, fig. 6. 



Original description. — " The corallum is short, and covers much 

 space. The corallites are very irregular in size, and the calices also. 

 The fossa is moderately deep, and presents a false columella. The 

 septa are thick, and unite laterally in sets of three, four, or six. The 

 free margin is faintly dentate. The largest calices have four cycles 

 of septa in six systems; but usually only three cycles are found in 

 smaller calices. The diameter of the calices is from one-tenth to 

 four-tenths inch 2.5 to 10 mm." 



Locality.— St. Croix, Trinidad. 



5. SIDERASTREA POURTALESI, new species. 



Plate 115, figs. 1, la. 

 1875. Siderastraea galaxea Pourtales, Geol. Mag., new ser., dec. 2, vol. 2, p. 545. 



The specimen identified by Pourtales as Siderastrea galaxea (Ellis 

 and Solander) = Siderastrea radians (Pallas) , the older name, is not 

 that species, but as it is closely related the following is a comparative 

 diagnosis. 



In growth, form, size of calices, and septal arrangement, Siderastrea 

 pourtalesi is similar to S. radians, but the wall is very thin, even 

 interrupted, zigzagging between the thick outer ends of the wedge- 

 shaped septa. The interseptal spaces are relatively wide and are 



1 Geol. Soc. London Quart. Journ., vol. 51, p. 279, 1895. 



2 Verrill, Conn. Acad. Arts and Sci. Trans., vol. 11, p. 155, 1902. 



