280 New Species of Crinoidea from the 



form similar to the type of A. ventricosvs ; but the body 

 is higher, and less spreading below the arms, while it has 

 a greater number of interradial and anal plates, and the 

 dome is nearly flat. 



The genus Aniphoracrinus, of Austin, includes species 

 having the structure of Actinocrinns, but having the mouth 

 lateral. This definition would embrace also those included 

 under the genus Ag-aricocrinus by Dr. Troost, the latter 

 name being applicable only to those with fiat or concave 

 bases, and having a somewhat peculiar arrangement of 

 the plates at the base of the arms, while the arms them- 

 selves are usually very strong, and a characteristic feature 

 of this group of crinoids. 



Ag-aricocrinus [Amphoracrimis) planoconvexus (n. s.). 

 Body plano-convex, basal portion flattened, with a mod- 

 erately depressed centre ; interradial and anal areas slight- 

 ly constricted and regularly rounded upwards at their 

 junction with the sides of the dome ; dome low, convex. 

 Basal plates small, concealed (in most specimens) by the 

 attachment of the column. Radial plates of moderate 

 size; second radial plates quadrangular; third radial plates 

 pentagonal, pointed above, supporting on each upper side 

 a very short, broad plate, on which rest the arm plates 

 proper. 



Interradial plates elongate, generally eight-sided, some- 

 times nine or ten-sided, succeeded by one and sometimes 

 two in the second series. First anal plate sub-hexagonal, 

 iiigher than wide, supporting three in the second range, 

 the lateral ones much the larger, with several small plates 

 irregularly arranged above, and uniting with the dome 

 plates. Dome composed of numerous small polygonal 

 plates, destitute of nodes ; the central plate near the anal 

 oi)ening is largest, and slightly convex. Arms unknown; 

 tlieir bases very large in proportion to the size of the body, 

 indicating great strength. 



