146 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



Echini vary in their progression from the ova to the adult state. 

 Thus he has come to understand to a certain extent, the structure, 

 homologies, anatomy, and physiology of the order. He has, with 

 extraordinary industry and care, watched their habits as far as he 

 could, from those within the range of his observation. He sub- 

 sequently visited every museum in Europe where type specimens 

 were preserved, and was even fortunate enough to discover the 

 types of some of the oldest authors. The result has been an 

 exhaustive monograph. It is a treatise en all that has been done 

 in the matter. It is also a history of the synonomy, and, as a 

 matter of course, its rectification. It contains besides, a judicious 

 arrangement of the genera, from a careful study of the relations 

 of each species. It is finally a descriptive catalogue, as perfect 

 as such a catalogue can be made in the present state of our 

 knowledge of all the known species. The amount of work thus 

 done is easily seen to be enormous. Dealing with the biblio- 

 graphy and synonomy alone would seem almost a labour of years. 

 The subject is one of especial interest and value just now, and 

 deserves all the attention it has received . A very small acquaint- 

 ance with Palaeontology will tell what an important element the 

 order is in estimating the earth's past history ; and now that 

 deep sea dredging has brought so many new friends and old 

 relations of Echini to light, the order may be said to be of the 

 utmost importance. .Urchins are generally better preserved than 

 most shells in strata, and being denizens of great depth, they 

 often remain to tell a tale when all else has disappeared. 



It will very likely be thought that very little is as yet known 

 of the Echini of Australia, but this would be a mistake. It is 

 true that no special study has been made of them, but many of 

 its species have a very wide range, and the coast has been pretty 

 well explored. 



A very extensive list of Australian species is contained in Prof. 

 Agassiz's volume, yet it is true to say, that beyond the fact 

 that such species exist on the coast, nothing beyond has been 

 ascertained. Now, Australia being a very large country, it is not 



