﻿292 Canadian Record of Science. 



is (|iute clear that these are the genera to which 

 Astrocystites is most closely allied, " Blastoids," writes- 

 Dr. Charles Eastman, in the first volume of his translation 

 of Zittel's Text-book of Palaeontology, published in 1896,. 

 '' have not been recognized, as such, up to the present, 

 time, in strata lower than the Silurian ; but it is possible 

 that several genera occurring in the Ordovician of jS'orth 

 America and liussia {Blastoidocrinus, Aster oUastus, etc.), 

 which are now referred to the Cystids, may eventually be 

 transferred to the Blastoidea." In that event, Astro- 

 cystites would, of course, have to be included in the same 

 category. On the other hand, Etheridge & Carpenter,, 

 on. page 129 of their " Catalogue of the Blastoidea in 

 the Geological Department of the British Museum," 

 published in 1886, say distinctly, " we have no certain 

 evidence of the existence of true Blastoidea anterior 

 to the Upper Silurian period. Eor we much doubt, as we 

 have explained in the previous chapter, whether the 

 problematical Blastoidocrimcs from the Lower Silurian of 

 Canada and Eussia can properly be referred to this, 

 group." Nicholson & Lyddeker, in the first volume of 

 their " Manual of Palieontology," published in 1889, follow 

 Johannes Muller's classification of the Cystoidea, and 

 divide the class " into the three orders of the Aporitidte 

 Diploporitidte and Khombiferi, according as the calycine 

 plates are imperforate, are pierced by yoked pairs of pores 

 indiscriminately distributed, or have their pores arranged 

 in pore-rhombs." Of these three orders, Astrocystites 

 would seem to be most probably referable to the 

 Diploporitidie. In conclusion, the writer begs to tender 

 his cordial thanks to his friend and colleague, Mr. L. M. 

 Lambe, F.G.S., for the accurate and original drawings 

 which are reproduced in this paper. 



Ottawa, April 28th, 1897. 



