No. 89.] 



123 



in their.first extension, are more or less rectangular to the axis and extended 

 •towards the ventral side, thus enclosing the upper part of the cavity; while, 

 either from the bifurcating plates, or from the upper margins of the simple 

 plates, these arms, or some of their subdivisions, are extended in a longitudinal 

 direction. 



The surflice is either granulose or striate, and the arms nodose or lamellose. 

 The accompanying diagrams will serve to illustrate the parts of the fossil, as 



described above. 



1 2 8 4 6 



CD 



m 



en 



ViaA 



Diagrams of Cheirocrinus chrysalis. 



Fig. 1. Diagram showing the relations of the parts, from the dorsal side. The small figures refer 

 to the parts of the fossil, and are correspondent with the succeeding diagrams. 



1. The basal plate, as seen when extended- 2. Lower dorsal plate, which in this 

 species is narrow and elongate. 3. Dorso-lateral plates. 4. Upper dorsal 

 or dorso -radial plate. 5, 5. Plates of the dorsal arm. 6, 6. Lateral bra- 

 chial plat-es. 7. Lateral arms and their subdivisions. 10. Point of column 

 of attachment. 



Fig. 2. Diagram of the ventral side : 8. The ventral arching plate. The arching cavity below 

 is filled by the recurved basal plate. 9, 9. Plates of the ventral side. 

 3, 3, are the extended ventral angles of the dcrso-lateral plates. 



Fig. 3. A ventral view of specimen in outline : 1, shows the ineuixed basal plate in its usual 

 position, filling the cavity below the ventral arch. 



Fig. 4. Lateral view of the same. 



Fig. 5. Dorsal view of the same specimen : 1, is the edge of the incurved basal plate, showing 

 below the dorso-lateral plates. 



CHEIROCRINUS CHRYSALIS ( n. sj. 

 Body small, subquadrangular; the plates arranged as shovrn in the diagrams 

 above. Lateral arms bifurcating. From the Niagara group. 



CHEIROCRINUS YENTRICOSUS ( n.s.). 

 Body ventricose; the interior cavity semielliptical below and circular above. Basal 

 plate broadly semielliptical; the first dorsal plate, the dorso-lateral plates, and 

 the ventral arch, all anchylosed together. The upper dorsal plate is deeply in- 

 serted between the dorso-lateral plates, and is longer than in any other species. 

 From the Burlington limestone. 



CHEIROCRINUS LAMELLOSUS ( n.s.). 

 Body unknown. Arms with strong lamellose extensions at the joints, 

 limestone. 



Burlington 



CHEIROCRINUS DACTYLUS ( n.s.). 

 Body small, subc3dindrical, flattened on the back. Plates of the body anchylosed. 

 Dorsal arm cylindrical nodose, bifurcating : lateral arms five on each side, rising 

 from the upper margins of five plates which proceed rectangularly from the 

 brachial plate on the upper lateral iace of the dorso-lateral plates. These arms 

 bifurcate twice, the bifurcating joint being nodose. From the Burlington lime- 

 stone. 



