185G.J - 75 



Basal pieces. The outer long ones descend lower than the middle pair and 

 tlie extremities of their pseudoambulacral lields are nearer the inferior extremi- 

 ties of the pieces. Their internal limb is narrow, lanceolate and obliquely trun- 

 cated above ; the external one is broadest, obtusch' triangular, and beni back- 

 wards at nearly right angles, to unite with the long basals and short radial, form- 

 ing with these a Hattened convex surface, whose transverse diameter equals the 

 total width of the calyx. The middle pair, or those standing over the small 

 basal, are more regular in form than the outer ones, their branches narrow and 

 equal. Thp internal edges of all the branches of the long radial pieces are limit- 

 ed by a fine carina, terminating below in a triangular projection, on which rest 

 the extremity of a pseudoambulacral field. The lateral sutures are also marked 

 by a fine carina. The short radial piece is sub-pentagonal and angulated in the 

 middle ; its length and breadth about equal. Below it rests by a double con- 

 cave edge on the extremities of the long basals ; the lateral edges are arched, the 

 outline of the superior edge somewhat V-shaped. 



Interrad'ud pieces. The three regular ones are swelled and rounded at the 

 apex, and terminate below in three salient angles ; the lateral edges are strongly 

 crenulated. The irregular pieces are situated on either side of the short radial. 

 They are scarcely more than half the width of the others, and only one of the lat- 

 eral edges is crenulated. 



Pseudoambulacral areas. The four linear areas are convex, and project above 

 the plane of the interradial plates. The pore pieces are transverse, sub-pentago- 

 nal and finely crenulated at their internal edges. Their surfaces are deeply in- 

 dented, and their number on each side of a field amounts to about thirty-five. 

 The supplementary pore pieces are sub triangular and very minute. The fifth 

 or anomalous area is small, triangular, and situated on the summit plane just 

 within and a little below the superior edge of the short radial piece. The pore 

 pieces are transverse, wide, and amount to about seven on each side of a field. 

 Their form and that of the supplementary pore pieces cannot be well made 

 out in the specimens on hand. The apertures situated at the extremities of the 

 pieces amount to about fourteen for the entire field. 



The Eleulherocrinus Cassedayi is the only known species of the genus. 



References to Plate II. 

 Fig. 1. Profile view of a specimen four times enlarged. 



2. Opposite view of the same, exhibiting the form of the short radial, 



and the prolonged part of the long basals. 



3. Basal view. 



4. Summit view, showing the anomalous pseudo-ambulacral field. 



5. A portion of one of the linear pseudo-ambulacral fields, very much 



enlarged. 



The report of the Corresponding Secretary for February and March 

 was read and adopted. 



On motion of Dr. Elwyn, it was Resolved, That the members of the 

 Methodist Conference, about to convene in this city, be invitrd to visit 

 the Museum of the Academy on public days, during the session of the 

 Conference. 



ELECTION. 



Mr. James E. Caldwell, Dr. Charles M. Cresson and Mr. A. J. 

 Brasier, all of Philadelphia, were elected Mrmbers, and 



Dr. F. V. Hayden, of St. Louis, Mo., was elected a Correspondent. 



