300 THE CEINOIDEA CAMERATA OF NOETH AMEEICA. 



Melocrinus Calvini W. and Sp. (nov. spec). 

 Plate XXIL Fig. 6. 



Similar to the preceding species, but the sides of the dorsal cup convex, 

 and the general form of the calyx subovoid; the basals less projecting; the 



radials, fixed brachials and interbrachials — the latter to the third row 



crowned by a large, rather conspicuous rounded node without other orna- 

 mentation ; the upper interbrachial and interambulacral plates a little 

 convex. 



Basals projecting laterally, and forming four rather conspicuous nodes 

 around the columnar attachment which is a little projecting. Radials and 

 costals longer than wide. The distichals of the same ray in contact laterally. 

 Regular interbrachial spaces large, but shghtly depressed between the arm 

 trunks; the plates arranged: 1, 2, 3, 3, the upper ones insensibly connecting 

 with the plates of the ventral disk. Anal interradius widest, having three 

 plates in the second row. Ventral disk short; the plates rather small and of 

 uniform size ; orals apparently unrepresented. Anus excentric, probably at 

 the end of a narrow tube. 



Horizon and Locality. — Hamilton group ; Johnson Co., Iowa. 



Tyjpe in the collection of Prof. S. Calvin of Iowa City, in whose honor 

 this rare species is named. 



Melocrinus oblongUS W. and Sp. (nov. spec). 



Plate XXIL Figs. 9 and 12, 



A rather slender species of less than medium size. Dorsal cup obconical ; 

 the sides straight to the top of the second costals, whence the rays turn out- 

 ward and form distinct lobes around the calyx, which give to the section 

 a decidedly pentalobate outline. Plates convex, a little nodose, but without 

 ornamentation. 



Basals small, subequal, notched at the sutures; the lower face but slightly 

 truncate, and very little excavated, Radials and first costals generally 

 longer than wide, especially the former; the second costals often as wide 

 as long. Distichals 2 X 10, the two upper ones axillary and separated by 

 a small interdistichal. The arm trunks not preserved in the specimens, but 

 as there are two distichals, the trunks must have been formed of two rows of 

 plates. The first interbrachial as large as the first costal; succeeded by 



