56 



BRIEF RESUME. 



In the ten Bulletins of the Illinois State Museum of Natural His- 

 tor}', commencing with the third and ending with the present one. 

 the authors have defined, from the palaeozoic rocks of Illinois, and 

 adjacent states, one new Order, the Conularida, five new families. 

 Enchostomidic. Mitrocrinida?. Pleurocystida?. Porocrinidas and Thai- 

 amocrinidie. and ten new genera. Aesiocystites, Belemnocystites, 

 Blairella, Emperocrinus, Enchostoma, Indianocrinus, Mitrocrinus, 

 Sampsonocrinus. Shumardocrinus and Thalamocrinus. 



We have described and illustrated more than foiir hundred new 

 species of fossils, nearly all of which belong to the Echinodermata. 

 Beside, we have redescribed and illustrated several species of other 

 authors which had been imperfectly described or not illustrated- 

 While doing this work, covering a period of nearly four years, we 

 have had the opportunity of examining the principal collections to 

 be found in these states, and we have, as we think, discovered many 

 things relating to the structure of crinoids that were before unknown. 

 The work must, however, speak for itself, as to our definition of the 

 anatomical parts, and the supposed biological functions performed 

 by them, and the supposed place in the scale of nature to which we 

 have referred the animals. 



