30 
AUG. F. FOERSTE 
Stelleroidea. In its present state of preservation, the most 
striking feature of this ray is the irregular series of short vertical 
pores along the anterior side of the concave depression traversing 
the actinal side of this ray longitudinally. These pores vary 
from 0.25 to 0.33 mm. in depth, and tend to occur in pairs, the 
members of each pair being less than 0.5 mm. apart, or sometimes 
so close together that two pores are included in the same general 
depression, appearing as separate pores only at the bottom of 
the larger elliptical pore formed by their union. 
A similar irregular series of vertical pores occurs along the 
anterior side of the longitudinal depression following the actinal 
side of ray II. Pores are not seen on the proximal parts of ray 
III, but on the distal part several pores occur along the middle 
of the longitudinal depression there visible. Vertical pores exist 
also along the middle of the deep depression following the actinal 
side of ray V. In the case of ray I, that part of the longitudinal 
depression which might show pores is over-arched by other 
plates, not seen on the other rays, probably because not pre- 
served there. No explanation for the presence of these pores 
can be offered. They appear closed at their inner extremities, 
and apparently bear no relation to the podial canals among the 
Auluroidea. At first they were regarded merely as borings, 
subsequent to the death of the animal, but in that case there 
appears to be no reason why their presence should be confined 
practically to definite parts along the longitudinal depressions 
following the actinal side of the specimen. The depression 
marked a in figure 2C on plate VI accompanying this paper 
probably represents an ordinary boring, and is quite different 
in size and depth from the pores just described. Moreover, 
there is no appearance of pairing in this case. 
The plates forming the abactinal side of the specimen,’ and 
these are almost the only plates here exposed, are so thick, and 
are so closely appressed at the sutures, that they must have 
been almost immovable. The thickness of the plates varies 
between 0.6 mm. to almost an entire millimeter, and may exceed 
this amount in some parts of the specimen, nearer the disk, 
where measurements, in the present state of exposure of the 
specimen, are impossible. 
