IIMTRODUCTION. 



In bringing my Monograph on the Asteroidea and Ophiuroidea to a close a few 

 words of explanation appear to be necessary in order to avoid any misconception as 

 to the cause that has occasioned delay in the completion of the work. 



When I had assembled for the first time all the materials I had collected for the 

 volume I found, much to my regret, that the specimens were fewer and more frag- 

 mentary than I anticipated, and that it was impossible to carry out the description of 

 the families in a manner similar to the one I had adopted in the Echinoidea. I 

 therefore determined to figure and describe all the species that I had collected and wait 

 for the discovery of others in public and private collections which I had not at that 

 period been able to inspect. The part containing the Asteroidea appeared in 1863, 

 and the part on the Ophiuroidea in 18GG. Since then I have made diligent search 

 among all collections that were likely to contain Jurassic Echinoderms, and after many a 

 hunt I have only succeeded in obtaining two additional species from these sources, aiul 

 finding a much better specimen of an important Yorkshire species, Astropecten rectus, 

 of which I have given a good figure. 



In the usual progress of discovery by waiting patiently for new things sometimes 

 a few specimens are met with, and I am happy to say that my patience has been 

 rewarded. Among the GoNiASTERiDiE a very fine specimen of Stellaster was collected 

 by my friend Samuel Sharp, Esq., E.G.S., from the ironstone beds of Inferior Oolite 

 near Northampton, certainly one of the finest fossil Star-fishes which the Inferior Oolite 

 has hitherto yielded up. An allied species was soon afterwards discovered in the 

 " Calcaire a Entroques," a bed of the same age, at Macon (Erance). 



a 



