FOSSIL CRUSTACEANS. 293 



We may judge of their extent in certain Formations, from 

 the fact, that in the cabinet of Count Munster, there are 

 nearly sixty species collected from a single stratum of the 

 Jurassic Limestone of Solenhofen. A rich harvest, there- 

 fore, remains in store for the Naturalist who will trace this 

 interesting subject through the entire series of Geological 

 formations. 



The analogies between existing species, and certain fossil 

 remains of Crustaceans have been beautifully illustrated by 

 the investigations of M. Desmarest. From him we learn, 

 that all the inequalities of the external shell in the living 

 species have constant relation to distinct compartments in 

 their internal organization. By the application of these dis- 

 tinctions to fossil species, he has pointed out a method of 

 comparing them with living Crustaceans in a new and un- 

 expected manner, and has established satisfactory analogies 

 between the extinct and existing members of this very nu- 

 merous Class, in cases where the legs and other parts on 

 which generic distributions have been founded, were entire- 

 ly wanting.* 



* H. Von Meyer has recently noticed five or six extinct genera of Ma- 

 crourous Decapods in the Musclielkalk of Germany. (Leonhardt and Bronn 

 Jahrbuch, 1835.) 



The subject of Einglish fossil Astacids (Crawfishes) is at this time re- 

 ceiving' important illustration in the able hands of Prof Phillips. 



In a recent communication to the Geological Society (June 10, 1835,) Mr. 

 Broderip describes some very interesting remains of Crustaceans from the 

 Lias at Lyme Regis, in the collection of Viscount Cole. In one of these, 

 the Lamell^e of the external Antennx, the form and situation of the eyes, 

 and other characters, show that it was a macrourous decapod intermediate be- 

 tween Palinurus and the Shrimps. 



A fragment of another macrourous decapod proves the existence at this 

 early period of a crustacean approaching to Palinurus, and as large as our 

 common Sea Crawfish. 



Two other specimens exhibit the breathing organs of another delicate 

 Crustacean, with the tips of the four larger and four smaller branchise pre- 

 served, and pointing towards the region of the heart, showing that these 

 fossil Crustaceans belonged to the highest division of the Macroura. They 



25* 



