88 PALEONTOLOGY OF NEW-YORK. 



The surface of the Echino-rncrinitcs is irregular, unequal, and embossed. The plates of the shell are 

 convex, sub-pyramidal, and ornamented with thick and reticulated striae. These stricP, always perpen- 

 dicular til the s'lles of the jitate, as in the Echinosphserites, form, by their combination in successive 

 chevrons, five or six rhombs radiating from the centre of these. The union of these rhombs forms triangles 

 inscribed one within the other where the plates are regular, or in part having a common base, whrn, by 

 the reduction of the sides of a plate, one of the rhombs become rudimentary The smallest of these 

 triangles, comprised between three faces of the pyramid, corresponds with the»angles of the plates of the 

 shell 



The Echino-encrinites is further distinguished by the presence of pores, not disseminated over the 

 entire surface as in the Echinosphajrites, but occupying a determinate place, and bordering three small 

 rhomboidal areas. These p 'res were only imperfectly defined by Schlotheim in his Eckinnspharites 

 granatvm and by M FIrrhan von Meyer in his Eckinn-encrinites senkenbergii ; it is to M, VoL- 

 B'-RTH that we are indebted for having exactly marked their place ( See Bull, de Saint- Petershourg, 

 Vol X., no. 19, pi. 1, fig. 4, 5, G ). Two of these poriferous rhombs are .situated near the base, and have 

 their gre-it diagonals united upon one of the angles of the opening where the stem is inserted ; while the 

 third is found on the opposite side, between the mouth and the great lateral opening, and directly above 

 the pentagonal basal [late : the two first are mounted upon the plates of the two inferior ranges, and the 

 last upon those of the two superior ranges. 



What was the design of these pores, or elongated grooves, which bound the three rhomboidal areas? 

 It would, doubtless, be difficult to affirm any thing on this subject : il is sufli.'ient to remark that these 

 pores are disposed according to the same law as in the Echinosphasrites, or the Hemicosmites ; that is to 

 say, that they part from the centre of the plates, and unite at their angles. The middle of the rhomboidal 

 areas are usually striated ; but the strife are less distinct than upon the rest of the crust, and appear some- 

 times a little w-orn The crust is in general solid, and crystallized in rhombohedrons as in all the crinoidea. 



The genus Erhiiin-encriniles has been established by M. Herman Von Meyer, in the Archives of 

 Kaustner, upon a specimen now unfortunately lost The description and the figure which he gives of 

 it are nevertheless exact enough to enable us to recognize, without hesitation, the fossil bodies of Saint- 

 Petersburgh, confounded by MM Pander and Bronn with the Echinosphaerites, and named by M. 

 EicHWALD GonocrvLiles. M. de Buch, struck with the impropriety of the name of M. Herman von 

 Meyer, has proposed, in his Memoire of this year, to change it for that of Si/cocijsli(e^. Although this 

 name, it must be allowed, may be better than that which we have adopted, we prefer to follow the rule 

 which we have imposed upon ourselves, to preserve always the most ancient names. 



The Echino-encrinites belong, as well as the Echinosphaerites, to the Lower Silurian system of 

 Russia. M. Volborth, to whom we owe a notice upon those of the environs of Saint-Petersburgh, 

 distinguishes three species of them in this country : the E. siriatiis, angulosus, and granatum. AVe 

 possess only the two first of these, and we do not believe that the third species is identical with the 

 Echiiiospkxritcs granatum ( Wahl.), to which this author compares it. Indeed, according to M. he 

 BticH, this last species, of which he makes the type of his genus Caryocystites, should have a very 

 different number of plates, and the striae not reticulated. The Echino-encrinites senkenbergii ( H. von 

 Meyer) constitutes probably a fourth species. M. Bronn, in his Lethaa Geognoslica, had reunited it 

 to \\\c Echinosplmriles granatum (Schlot.); but in the additions and corrections of the same work, 

 p. 1284, he says that M. Herman von Meyer has shown that this reunion has no foundation. 



The Echino-encrinites appear exclusively to belong to Russia; at least we do not know of their 

 occurrence elsewhere. If the Cornulites serpularius is only a part of their stem, there is reason to believe, 

 nevertheless, that they will be found in Gothland and in England, where this singular body has been 

 discovered. {Geology of Russia and the Ural Mountains, Vol. ii. pp. 27, 2S & 29.) 



