r)2 



Tliere is of coiu'se some resciublance between all species of 

 Bdlocn'inis Imving, as in tins case, a snbequal calyx and vault; 

 but there is no necessity for comparing this species with any of 

 them bearing eighteen arms, as the least care will distinguisii it. 



Found in the Kaskaskia Group, on Little Barren river, and now 

 ill the collection of \Vm. F. E. Gurley. 



13AT0CUINUS SACCDLUS, U. Sp. 



riiitr J'", Fit;!. 7', view of calyx, vault and, part of the column, op- 



ixisitotliedzygmisarea; Fig. S, hasiil vieir. nzijgoiis side 



up: Fig. 9. siumnit virif of s'lnie. azygous side doivn. 



Body medium size. Calyx somewhat saucer-shaped, three times 

 as wide as high: arms directed horizontally; plates convex; sutures 

 distinct; surface granular. Our specimen is a little depressed be- 

 low, so as to produce an unnatural concavity around the column, 

 and, therefore, does not show the full height of the calyx; it ap- 

 pears to be four times as wide as high, but remove the depres- 

 sion and it will not be more than three times as wide as high. 

 The column is round, and plates rather thick and beveled toward 

 the sutures so as to make them sharply angular in the middle. 



Basals small, low, and extending only a little beyond the column. 

 First radials small, one-half wider than high. Second I'adials two- 

 thirds as large as the first, quadrangular and only a little wider 

 than long. Third radials very little larger than the second, four 

 pentagonal, the one opposite the azygons area heptagonal, axil- 

 lary and bear upon each upper sloping side the secondarj' 

 radials. There are two secondary radials in each series, four of 

 which are axillary and bear upon each upper sloping side a 

 tertiary radial. In the ray opposite the azygous area the second 

 secondary radials are rather large and bear the fi-ee arms. This 

 gives to the species eighteen arms. The arms ai-e small and directed 

 horizontally. 



There are three plates in each regular interradial area, the first 

 are the larger plates of the calyx, and each is followed by two 

 rather long plate'-. In one or two of the areas there is a small 

 plate above these. The first azygous plate is a little larger than the 

 first radials and it is followed by four plates in the second series; 

 a])ove these the sutures are obscure in our specimens but appar- 

 ently there are three in the third series and above these there is 

 one or two plates that connect with the plates of the vault. 



