New Species of Fossils. 209 



The arrangement of the plates forming the calyx is similar to 

 that in Dendrocrinus, except that the regularity of the radial series 

 of plates is not broken by the interposition of the anal plates. In 

 this respect Merocrinus is allied to Iocrinus, and also in the posi- 

 tion of the plates supporting the anal tube. It differs from Iocrinus 

 in having a well-developed ring of underbasals, and also in the gen- 

 eral appearance of the entire body. 



The accompanying diagram gives 



Y« c2<^> the arrangement of the plates of the 



eg 7 calyx and a portion of the arms. 



<g? 

 a? i=Column. ii=Underbasals. 



^/d a Qv2 iii=Basals. iv=Radials. v=Brach- 



@<2s% r\$$^ iak vi==Free arms - a==piat e su p- 



rvl^^A porting brachial plates and those of 



™\£Tc$ ^ the posterior side of the anal tube. 



Merocrinus typus, n. sp. 

 Plate 17, fig. 5. 



Calyx of medium size, broad at the base and gradually enlarging 

 to a diameter one-third greater at the base of the arms. 



Underbasals pentagonal, low and broad, very obtusely wedge-shape 

 above. Basals hexagonal twice as wide as high, alternating with the 

 underbasals below and the radials above. Kadials pentangular, con- 

 siderably broader than high, broadly wedge-shape at the base and 

 narrowing slightly towards the upper margin. 



The first right postero-lateral plate above the radial is pentagonal 

 and supports the brachial plates on its right sloping side, and on the 

 left the posterior wall of the anal tube. The brachial plates are 

 quadrangular, broader than high. The first bifurcation of the right 

 postero-lateral ray occurs on the sixth plate above the bifurcating 

 plate below, and that of the left ray on the sixth plate above the 

 radial ring of plates, each division again bifurcating on the ninth or 

 tenth plate above. 



The posterior plates of the anal tube are a little broader than high, 

 decreasing in width towards the summit. The rounded posterior 

 side of these plates gives this, the only portion of the anal tube ob- 

 served, the appearance of an arm extending up between the true 

 arms. Other portions of the anal tube not observed. 



Surface of the plates slightly roughened. 



The portion of the column attached to the calyx is formed of thin 

 round plates closely united. 



Formation and locality. Upper part of the Trenton limestone, 

 Trenton Falls, New York. 



