182 SYNOPSIS OF THE CHARACTERS OF THE 



ACTINOCRINUS GLOBOSUS. PJdl. 

 Actinocrinus globosus. Phil. Geol. York. 

 One or two very obscure casts have been, with doubt, referred to this species. Tlie globular form and 

 concave base are identical, but the plates of the body are not visible. 



Actinocrinus l^evis. Mill. 



Actinocrinites Irevis. Mill. Hist. Crin. 

 Several imperfect specimens, referrible to this species, have occurred ; the smoothness of the plates are the 

 principal distinction from the A. triacontadactylus . 



Actinocrinus polydactylus. Mill. 



Actinocrinites polydactylus. Mill. Crin Actinocrinus polydactylus. Phil. Geol. York. 



gp^ C/j. — Five arms, each having two hands, terminating in four or five fingers. 



This is a smaller species than the A. triacontadactylus, but closely resembles it in many of the details; 

 the muscular ridges are much more distinct, however, and it is at once distinguished by the greater number of 

 its fingers; the pectoral plates, when contracted, shew the remarkable character of being palmated, and divided 

 into several points or branches ; abundant in the limestone of Hook Head, some specimens exhibiting the 

 column upwards of a foot in length (imperfect), the body, arms, hands, fingers, tentacula, proboscis, &c. in 

 situ. 



Actinocrinus pusillus. M'Coy. (PI. XXVI. fig. 4). 



Sp. Ch. — Body staall, globose, surface of the plates ornamented with minute, curved lines and dots. 



This Actinocrinite does not appear ever to attain the size of a large hazel nut ; it differs from all of its 

 genus in the beautifully ornamented j^lates of the body, which, under the lens, appear sculptured in the most 

 delicate manner, with raised, twisted lines and isolated points, over which the strong muscular ridges pass. The 

 pelvis is small, flattened at the base, supporting six large costals ; the intercostals are hexagonal, and about 

 equal to the second costals in size ; the scapulae are small, each supporting an arm, having two hands. Length 

 six lines, width six lines. Occurs in great numbers in one locality. 



Actinocrinus tenuistriatus. Pli.il. 



Actinocrinus tenuistriatus. Phil. Pal. Fos. 



I have observed several joints of vic^jwocrMms answering perfectly to Professor Phillips's figure and de- 

 scription of this species ; they are chiefly remarkable for the fineness of their striae of articulation, and the uni- 

 form thinness of the joints. 



Actinocrinus tessellatus. PJdl. 



Actinocrinus tessellatus. Phil. Geol. York. 



Sp. Ch. — First costals large, hexagonal; three upper sides nearly equal and shortest; second costals hex- 

 agonal; all the sides nearly equal; scapulae heptagonal; surface of the plates nearly smooth, slightly marked at 

 the edges with short, muscular ridges. 



This species is very rare ; the peculiar form of the scapula distinguish it from the allied species. 



Actinocrinus triacontadactylus. Mill. 



Actinocrinus triacontadactylus. Mill. Crin Actinocrinus triacontadactylus. Phil. Geol. York. 



Sp. Ch. — Scapulae hexagonal, supporting five arms, having each two hands provided with three fingers 

 each. 



