MELOCEINID^. 299 



known, composed of rather small pieces. Form and position of anus un- 

 known. Column round, strong; the nodal joints projecting, the intervening 

 ones knife-like. 



Horizon and Locality. — Hamilton group ; Canandaigua Lake, N. Y. 



2'ype in the collection of Prof. J. M. Clarke, now in the State Museum at 

 Albany. 



Melocrinus Tiffanyi W. and Sp. (nov. spec). 



Plate XXII. Figs. 7a, h. 



Calyx pyriform ; the sides nearly straight from the top of the basals to 

 near the bases of the arms ; the tegmen depressed-hemispherical ; cross- 

 section, as seen from above, obtusely pentangular. Surface of plates orna- 

 mented by faint ridges, radiating from near the centre of the plates to the 

 centre of adjoining ones. 



Basals projecting laterally, forming four conspicuous, elongate nodes; 

 the lower part somewhat excavated for the reception of the column. Eadials 

 and costals gradually decreasing in size upwards, about as long as wide; the 

 second costals not more than half the size of the radials. Of the distichals 

 two plates are preserved; the lower one fully one half smaller than the 

 preceding axillary ; the second short, shaped like an arm joint and curving 

 outwards. There are no interdistichals, all plates of the arm trunks being in 

 contact laterally. Interradial areas on a plane with the radials and costals; 

 the first interbrachial the same size as the radials, and followed in the type 

 specimen by two plates at three of the sides, but in the posterior and right 

 antero-lateral interradius by three, and these by numerous rows of from 

 three to four plates, which connect with the disk pieces. Ventral disk 

 depressed-hemispherical, the plates very uniform, rather large, having the 

 size of the third row of interbrachials. They are ornamented hke the plates 

 of the dorsal cup, but are a little more convex. There are apparently no 

 orals. Anus excentric, probably connected with a tube. Arms unknown ; 

 column round. 



Horizoji and Locality. — Hamilton group ; New Buffalo, Iowa. 



Ti/pe in the collection of Mr. S. A. Tiffany of Davenport. 



