242 



PALXONTOLOBT OF NEW-YOIIK. 



FRAGMENTS OF COLUMNS OF CYSTIDE^. 



PLATE L. Fi-s. 19 - 2<J. 



Fig. 19. Several joints of a column, near the base, having the joints connected and reflexed, 



with the margins strongly crenulate. 

 Fig. 20. An enlargement of two joints from the preceding figure. 

 Fig. 21. A fragment of a column where the joints are composed of interrupted plates, which 



extend only a short distance, gradually thinning away, and being overlaid by the thin 



edge of another one. The plates are reflexed towards the outer margin. 

 Fig. 22. An enlargement of the same. 

 Fig. 23 and 24. A fragment of a column with the joints carinated and reflexed on their outer 



margins, and finely crenulate. 



The separate plates figs. 25 and 26, 27 and 28, belong to the same or a similar 



species. The exterior surface of 27 is covered with a minute coral like Aulcpoha, and 



the ornament has been obliterated. Fig. 28 is the inside of the same plate, showing 



concentric lines of growth. 

 Fig. 29. An enlargement of the small branching coral on fig. 27. 



Position and locality. The specimens figured are from the shale in the vicinity of Lockport 



{Collection of Col. Jcwett.) 



Genus APIOCYSTITES (Forbes). 



" Corpus oblongum, tetragonum, rhombiferum, angulis truncatis, excavatis ; brachia quatuor 

 " plana, in sulcis angulorum inclusa ; sulci brachialesobliqui-lobulati. Os Iransversum, apicale ; 

 " anus lateralis, subapicalis ; ossicula ovariales laterales sex. Assulee basalts 4 ; infra-ovariales 

 " 5 ; centro-laterales 5 ; supra-ovariales 5 ; apicalis ? Basis plana. Columna 1" 



The essential characters of this genus appear to me to be so nearly represented in our spe- 

 cimens, that I am unwilling to give another name at present ; though a strict interpretation 

 may render it necessary, if the discovery of other species shows the same differences. The form 

 and arrangement of the plates of the base and second series are precisely as in Apiocvstites. 

 The plates bearing the higher pectinated apertures are also of the third and fourth series. In 

 our species, however, the plates of the ovarian pyramid are distinctly five, as counted in two 

 well preserved specimens ; and the plates surrounding them (circa-ovarian plates) are ten. 

 The plate arching over this aperture is sometimes simple, and sometimes divided into three, in 

 the same species ; but the apex of this plate does not reach the summit, and should be considered 

 as belonging to the third series entirely. The only point which can be regarded as the mouth, 

 is a subtriangular elevation with a spreading border, situated on the left side a little below the 

 apex, and rising from one of the plates at the base of the arms. The arms are almost similar to 

 those of the preceding genus, except that they consist of two distinct pairs, composetl of a 

 double row of joints, each row consisting of unequal plates j the alternate ones being similar, 



