80 The Ottawa Naturalist. [Oct. 



which connect the centres of the plates, forming a series of tri- 

 angles. 



Figure 1x2. Figure 2 x 2. 



The other specimen is a part of the dorsal cup, lacking the 

 basal portion. Figure 2 shows this fragment, the ray lacking 

 the distichial being the anterior radius. The rays show a strong 

 longitudinal ridge crossing the first costal and bifurcating near 

 the centre of the second, sending a branch onto each of the dis- 

 tichials. This species appears to agree with Mariacrinus 

 warreni from the Niagara in having only two distichials, and 

 no palmers in the calyx. In fact, none of the rays show more 

 than one cycle of distichials, but there were probably two when 

 the specimen was complete. 



The interradial areas are not depressed as in most species 

 of this genus, a section through the calyx at the second cycle 

 of interbrachials being almost circular in outline. There is, 

 however, a slight depression in the interdistichial spaces. The 

 first interbrachial is large, the next two slightly smaller. The 

 three plates of the third series and the four of the fourth are not 

 regularly hexagonal, but laterally compressed. The posterior 

 interradius is very badly preserved, but there appear to be five 

 interbrachials in the third row. As shown in the figure the 

 plates are ornamented with raised lines connecting the centres 

 of the plates. 



Locality. The specimens were found by the writer in the 

 limestone of the Three Forks Shale at Logan, Montana, asso- 

 ciated with the fossils of the brachiopod facies of the Clymenia 

 americana fauna. The tvpes are in the Carnegie Museum, 

 Pittsburgh, Penna. 



GENUS SCHCENASTER MEEK AND WORTHEN. 

 SCHCENASTER? MONTANUS SP. NOV. 



Animal small, about an inch in diameter. Rays short, 

 slender, extending about one-half their length beyond the disk. 

 Disk large, pentagonal, the margin slightly concave between 

 the rays. The five proximal plates of the adambulacreal series 

 function as orals, while on the arms beyond the disk the adam- 



