SECONDARY AND TERTIARY FORMATIONS OF NORTH AMERICA 123 



Colony fixed, encrusting submarine bodies, composed of only one layer of juxta- 

 posed cellules, arranged in quincunx, oval or hexagonal, convex, Hat or concave on 

 their surface, which is sometimes entire, sometimes cribrate. Mouth variable in form, 

 of moderate size and placed in advance. No special pores, but provided with ovarian 

 vesicles placed in advance of the mouth. Sometimes we find, in place of an ordinary 

 cellule, an accessory cellule, always differing in a marked manner from the ordinary 

 ones. Colony sometimes nearly circular, sometimes increasing only from one margin, 

 so as to present an irregular form. The latter, with various modifications, is by far 

 the most common mode. 



This genus can be at once distinguished by its having simple cellules, without spe- 

 cial pores or fossets, encrusting other bodies, always in only one layer. 



History. — There has been so much confusion in the use of this generic name, that 

 we deem it advisable to copy a condensed account of its history, which will also serve 

 to point out its synonymy, from d'Orbigny's carefully prepared sketch given in his 

 " Paleontologie Franchise, Terrains Cretaces," vol. 5, p. 390, et seq. The first distinc- 

 tive name given to the genus was Cellepora, given by Fabricius in his Fauna Grozn- 

 landica in 1780. He then described six species under this name, only one of which 

 does not belong to it, as now circumscribed. Pallas, in 1766, had confounded the 

 genus with Eschara, F lustra, &c, In 1789 Gmelin, in his compilation of Systema 

 Naturae, retained Pallas' name, and added other species belonging to Celleporaria and 

 Semicelleporaria. Esper went further, and in 1791 placed in Cellepora of Fabricius, 

 besides the last two genera, Idmonea and Eschara. In 1801, Lamarck, rejecting the 

 five species of Fabricius, took the sixth for his type, confining the genus to those 

 species having many layers of cellules. Moll, in describing the species of the Mediter- 

 ranean, gave them, with many other genera, under the name of Eschara. Lamoroux, 

 in 1812 and 1816, took the five species as types and restricted the genus to the species 

 with one layer. In 1816 Lamarck made his genus Discopora (including some true 

 Celleporae, with some with many layers and some other genera) and gave as the dis- 

 tinguishing characters that the cellules were in irregular quincunx and not salliant. 

 Lamoroux, in 1821, removed the many layered species of Lamarck from Cellepora 

 to constitute his genus Celleporaria. Goldfuss placed only true Cellepora: in this 

 genus. The Cellepora of Edwards. 1836, is the Celleporaria of Lamaroux, 1821. The 

 former, at that time made of Cellepora, Fabricius, Lamoroux and Goldfuss, two new 

 genera — Escharina for the species in which the cellules are horizontal in their mode 

 of grouping, and Eacharoides for the species in which the cellules are oblique or nearly 

 vertical ; he also retained Discopora, restricting it to the species in which the separa- 

 tion of the cellules is not distinct exteriorly. That these three forms mer°-e 

 into each other will be evident on examining a comparatively small number of 

 species. 



■ VI 



