LOWER HELDERBERG ROCKS. 
B 49 
FURTHER OBSERVATIONS ON THE CYSTIDEiE. 
The Memoir of Von Buch “Uber Cystideen”, published in 1845, giving 
the result of his researches upon the structure and relations of these fossil 
bodies, created a new interest in the subject of his philosophical investiga¬ 
tions. Although these bodies had long been known, and several species 
described by various authors, their zoological affinities and relations had 
not been clearly indicated; and no attempt had been made to separate 
them as a group from the Crinoideae, until Wahlenberg in 1821 suggested 
that they were animals intermediate to the Sea-urchins, Echinideae and 
Crinoids. This writer describes, nnder the name Echinosybarites, three 
species which had previously been described as Echinus by Gyllenhal and 
Hisinger. 
M. Yon Buch has advanced the opinion that these bodies constitute a 
distinct order of Ecliinodermata, inferior to the Crinoids; and this view 
has been followed by M. de Verneuil, while Volborth, Pictet, and others 
have maintained that they are true Crinoids. 
Prof. Edward Forbes, in his Memoir upon the Cystideae of the Silurian 
rocks of the British islands (Memoirs of the Geol. Survey, Yol. ii, part 
ii, 1848), maintains the opinion first advanced by Wahlenberg regarding 
the relations of these bodies; presenting a very interesting and philoso¬ 
phical essay upon the subject, which has been more fully noticed in the 
second volume of the Palaeontology of New-York. 
Without intending in this place any discussion of the question of the 
relations of these fossils, it may be interesting to notice the progress of 
our knowledge regarding them, and the additional genera and species 
which have been published since the date of the Memoir of Von Buch. 
In this memoir five genera are described, viz : Hemicosmites, Crypto- 
crinites , Caryocystites, Echinoencrinites (= Sycocystites ), and Echinosybarites 
( = Spharonites). Prof. Forbes, in his memoir cited, has added Apiocystites, 
Pseudocrinites, Prunocystites and Agelacrinus. In the second volume of the 
Palaeontology of New-York there have been added Callocystites, Hemi- 
