Mr. Silliman, Jr. on the Composition of Corals. 189 
resemblance to the Styline and Caryophylliz, but differ in internal 
structure. ; 
This genus was instituted by Lamarck for a few unlike species, char- 
acterized by consisting of parallel stems or tubes, and has been retain- 
ed in treatises with the same indefinite characteristics. The Madrepora 
organum of Linneus is best determined, and appears entitled to rank 
as the type of the genus, and has been so considered in this place. 
The characters have been drawn from the figures by Fougt and Schweig- 
ger, and from a specimen examined by the author. Other cylindrical 
fossil species, similar in external habit, belong to the genera Amplexus, 
Cyathophyllum, or some one of the preceding groups. 
Fougt, Amen. Acad., i, tab. 4, fig. 6, and No. 1; Schweigger, 
Beobacht., pl.7, fig. 66, and Handb., 419; Lamarck, 2d ed., ii, 340; 
Blainville, Man., 348; Goldfuss, Petrefakten, tab. 74. 
Arr. 1V.—On the Chemical Composition of the Calcareous Co- 
7 rals; by B, Sitrman, Jr. 
Tuts article is from the work on Zoophytes, by J. D. Dana,f 
for which the researches were undertaken. This volume is just 
out of press, but can hardly be said to have been published, 
since the small number of copies printed (only to hundred) will 
enable very few even of those most interested ever to see the 
work. The investigations have led to some unexpected results, 
which will be found to have an important bearing on the subject 
of geology ; especially as serving to explain in a more rational 
way than any heretofore offered, the origin of those rarer ingredi- 
ents in metamorphic limestones and other rocks of animal deriva- 
tion; which have always been a puzzle to geologists. 
No extended researches on the chemical constitution of co- 
rals have been made, it is believed, since Mr. Hatchett’s, already 
cited by Mr. Dana. This chemist did not operate quantitatively 
* In Vol. xxvu, p. 135, of this Journal, some earlier results obtained by me on 
this subject were stated, which were prematurely published, and greatly errone- 
ous. The best antidote to an error of this sort is the early publication of correct 
and trustworthy results. It is to be hoped that the researches detailed in this pa- 
per are of this description, and the attention of those interested in such studies 
is invited to the repetition of the analyses here given. The geological interest of 
se observations is not in any way lessened by the results recently obtained, al- 
though differing so much from those previously published.—S. 
t See ante, page 178, for the title, &c. 
= 
