MONOGRAPH OF THE ECHINODERMATA. 499 



the branches which I have found do not merely ramify on the 

 surface, but also in many instances pervade every part of the 

 interior of the stone. Still I cannot help thinking, from their 

 being described as " resembling branches flattened by pres- 

 sure," that they will on comparison be found allied to them ; 

 and if so, another locality, many miles distant from mine, 

 must be added. 



[t will be observed that some of the fossils are almost black. 

 This has arisen from the use of diluted muriatic acid when I 

 first began to clean them, which acted powerfully on the fos- 

 sil as well as the matrix. It is, however, necessary to notice 

 that in many instances the fossil itself is of a dark colour. 



I trust that when the nature of these remains is more fully 

 made out, additional light will be thrown on some of those 

 singular forms of the flint which are often discovered in the 

 chalk formation, and the origin of many of which still remains 

 in obscurity. From several specimens of flint which I have 

 examined, I am of opinion that these curious fossils do actu- 

 ally occur in this formation ; and it appears the more proba- 

 ble, from the fact that several of the same genera, 1 and at 

 least one species of shell {Terebratula strlatula), are found 

 in both strata. 



Highgaie, May 15, 1839. 



REVIEWS. 



Art. I. — Monographie des Echinodermes. Par Lotus Agassiz. Neuchatel. 



Livraison 1. 



It is with extreme satisfaction that we see Professor Agassiz 

 commencing the publication of an illustrated Monograph 

 upon the Echinodermata. The remarkable forms of the 

 Echinites, and the excellent state of preservation in which 

 the fossil species are found, have always rendered them 

 objects of interest, and constantly attracted the notice of 

 naturalists. Our own countryman, Dr. Woodward, in the 

 catalogue of his famous collection, was probably among the 

 first who attempted their classification, which was followed 

 by many of the early writers. He adopted a twofold divi- 

 sion ; — first, the Spatagi, having two openings, either both 

 at the base of the shell, or one at the edge or centre of the 

 base, and the other near to, or in, the opposite margin ; and 



1 For example, the Nautilus, Pentacrinite, Ophiura, Spatangus, &c. I 

 have also found in the matrix, in close contact with my fossils, Spirolinites, 

 and a species of Rotalia, 



