44 STRUCTURE OF THE CYSTIDE^. 



which are visible either upon the outer or on the inner side of 

 the plates, in such a manner that the united pores belong to two 

 different adjacent plates. 



" a. Pore-rhombs without external connexion of the pores. 

 Hemicosmites and Caryocrinus ; in Hemicosmkes the combining grooves 

 are according to Volborth, upon the inner surface of the plates. 



"6. In Echinosphcerites granatum, Wahlenb. {Caryocystites p-anatum, 

 V. B.), the pores are united by bands projecting externally, which 

 contain the connecting canal of the pores, and this canal is always 

 a single one between each pair of pores, or even a series of pores.* 

 The more importance is to be attached to this circumstance, as 

 the number of the calycine plates, even of the basal plates in 

 Caryocystites granatum, varies, so that some specimens possess more 

 superimposed plates than others, and even specimens with five 

 basal plates are not rare. According to the arrangement of the 

 plates, I do not think that Caryocystites and Echinosphcerites could 

 be separated. 



" A form nearly allied to Caryocystites granatum, observed by M. 

 Beyrich (Drift \_Geschiehe'\ near Berlin), the plates of whose calyx 

 are more numerous, is distinguished by the bands which unite 

 the pores belonging to an entire series of pores, which penetrate 

 the entire thickness of the plates, so that the series of pores 

 appear also upon the inner surface of the plates. Something similar 

 may also be observed in many specimens of Caryocystites granatum, 

 inasmuch as the canals of the bands not unfrequently also exhibit 

 clefts here and there between the terminal pores. These clefts 

 may indeed be readily explained by the grinding down of the 

 canals ; the occurence of the regular rows of pores in the species 

 above mentioned, however, leads us to question whether they always 

 have this origin. 



'* c. In Echinosphcerites aurantium and E. aranca every two pores of 

 two plates are not uncommonly connected by one, usually by two 

 canals, which are recognizable upon the outer surface of the plates ; 

 Echinospharitcs testudinarius, included by Von Buch in the ill- defined 

 genus Caryocystites, is an elongated Echinosphaerite. Its pore- 

 rhombs agree more closely with the previously-named species than 

 with Caryocystites granatum, though the number of the pore-canals 

 between every pair of pores is in some localities still greater. 



* und (lieser Canal ist immer ein einziger zwischen je zwei Poren, oder selbst 



einer Porenreihe. 



