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Genus FavositEs (Lamarck). 
The genus Favosites (Lamarck), comprises branched or massive corals, composed of numer- 
.ous more or less polygonal corallites, which are divided internally by transverse partitions or 
“ tabulee,” sometimes quite rudimentary. The walls of the corallites are perforated by one, 
two, three, or more rows of “‘ mural pores,” by which the separate corallites are placed in 
communication, The septa are absent or rudimentary, being at most represented by tuber- 
cles or short spines. 
The generic limits of Favosites have not been universally agreed upon by paleontologists, 
and the genera Hmmonsia, (Kidw. and H.), and Astroceriwm (Hall), have been founded upon 
differences which Mr. Billings rightly regards as not of generic value. Thus, Hmmonsiais 
distinguished from Favosites simply by the incompleteness of the tabule; but this same 
peculiarity can sometimes be observed even in F. Gothlandica, the type-species of Favosites, indi- 
vidual examples of which not very uncommonly exhibit portions with the complete tabulz of 
Favosites and other portions with the imperfect tabulee of Hmmonsia. In the same way, there 
are many examples of Yavosites, of more than one species, in which the tabulee, whether natu- 
rally or from some peculiarity in the manner in which they were preserved, are quite rudi- 
mentary and areeven more imperfect than they are in ordinary specimens of Favosites hemis- 
pherica, upon which the genus Emmonsia was founded. 
The genus Astrocerium, again, was founded by Hall (Pal. New York, Vol. 2, p. 120,) to 
include corals exceedingly like Favosites in all superficial characters, but differing in the pos- 
session of spiniform septa. It would appear, also, though this character is not specially 
mentioned, that Hall believed the corals which he referred to Astroceriwm to be destitute of 
mural pores. This latter point, if it could be proved, would amply suffice to separate Astro- 
cerium generically from Favosites ; but there is much reason to think that the apparent absence 
of mural pores may be due to mineralisation merely. At any rate, it is far from uncommon 
to meet with examples of undoubted species of Yavosites in which no pores can be detected. 
The other point—namely, the presence of spiniform septa—is also not a satisfactory distine- 
tion, partly because some examples of /avosites exhibit the same thing, and partly because 
some examples which would generally be referred to Astrocerium from their geological position 
and general appearance, are without any traces of septa. Upon the whole, therefore, it would 
appear that the genera Astrocerium and Emmonsia can not be retained. 
The numerous species of Favosites may be divided into two groups, according as they are 
massive or ramose, F. Gothlandica being the type of the former, and F’. polymorpha of the 
Jatter. The characters which have been relied on as separating the species of this genus are 
chiefly the following :—1. The diameter of the corallites; 2. The equality or inequality in 
size presented by the corallites ; 3. The completeness or incompleteness of the tabule ; 4. The 
number of rows of mural pores; 5. The position of the mural pores, whether on the flat faces 
of the polygonal corallites or on their angles ; 6. The presence or absence of rudimentary 
septa. For convenience of reference the more important species of Favosites may be arranged 
as in the following table, it being remembered that some of the species here enumerated, are 
perhaps not valid, and the characters derived from the number of rows of mural pores are not 
constant, even in the limits of the same species :— 
A. MAssiIve Sprcrss. 
a. Tabulz complete. One row of mural pores, placed on the faces of the corallites. 
1. Favosites basultica (Gold). 
2. Favosites turbinata (Billings). 
b. Tabule complete. Two rows of mural pores, placed on the faces of the corallites. 
3. Favosites Gothlandica (liam). 
4. Favosites Niagarensis (Hall). 
c. Tabulee complete. Three rows of mural pores, placed on the faces of the corallites. 
5. Favosites multiporu (Lonsd). 
; 6. Favosites Troosti (Kdwards and Haime). 
d. Tabule complete. Mural pores situated in the angles formed by the prismatic walls 
.of the corallites. , 
7. Favosites alveolaris (Gold). 
8. Favosites aspera (D’Orb). 
