3T6 PROCEEDINGS OF THE ACADEMY OF [1881. 



arranges systematically next to the Taxocrlnidse. It cannot be 

 denied that Sagenocr. expanaus, in its general structure, and par- 

 ticularly in the arms, resembles some species of Taxocrinus, but 

 the body lacks entirely the articulate structure. Zittel places it 

 in a subdivision of the Glyptocrinidae. 



Generic Diagnosis — General form including arms, oblong. 

 Calyx cyathiform ; without ridges along the radial regions, and 

 without marked surface ornamentation ; symmetry slightly bi- 

 lateral. 



Underbasals three, unequal, anchylosed, forming a pentjtgon. 

 Basals five,^ differing somewhat in form, generally four of them 

 acute above, the fifth truncate. Primary radials 3 X 5, of nearly 

 equal size, the first and third of a like form, but reversed. 

 Secondarj'^ radials 4X10, rather large, their upper and lower 

 sides parallel. The upper plate bifurcating, giving off from each 

 side a primary arm — making twenty in all — which at intervals 

 divide again. The branches are toward the inner side of the ray, 

 and remain simple throughout. The arms taper rapidly near the 

 ends, and — if the fragment figured by Angelin, Iconogr., PI. 28, 

 fig. 8, belongs to this genus, of which we entertain some doubt — 

 the upper parts coil spirally inward once or twice. _ They are 

 composed of single joints, which are wide and short, quadrangu- 

 lar, with sutures nearly parallel, except the bifurcating plates 

 which are depressed pentagonal. Pinnules short (Angelin\ 



Interradial spaces not depressed, plates numerous, composed 

 of four or more series of two plates each, very graduall}- decreas- 

 ing in size. The first plate rests deeply between the first radials, 

 almost touching the upper angle of the basals. The first anal 

 plate rests upon the truncate side of the posterior basal, support- 

 ing two plates in the second, and three in the third series. Inter- 

 axillaries one or more. 



General form and structure of the vault not known, but it 

 evidently was elevated near the arm regions, and composed of a 

 large number of small plates. Anus unknown. 



The column, according to Angelin (PI. 21, fig. 8), is tripartite (?) 

 and perforated with a large pentalobate canal. 



* Angelin gives the number of basals (parabasals) as six, which is evi- 

 dently a mistake, nor do we believe that the sixth plate represents an anal 

 plate, as no plate of that kind has ever been observed below the line of 

 radials. 



