264 



tliat in a direct lateral view they appéar aboul four times as broad as high; they are tlms 

 much shorter than the radials of the species of Atelecrinus. 



l'li<- arms are five in number, very stout and probably also very long. All are broken 

 off at the base, the longest stump measuring ui mm. from the subradial clefi to the distal 

 border of the tenth brachial. 



I e first brachial is slighdy over twice as broad as its lateral length, and is basally 

 j nst in apposition with its neighbors; th<- later, il edges are approxi matelj perpendicular to the 

 proximal border; there is a deep notch in the distal outer angle. The second brachial is very 

 irregularly quadrate, the longer side longer than the sides of the first, the shorter about the 

 width of the pinnule which it bears, and somewhat pmduced ventrally; there is a strong but 

 evenlj rounded synarthrial tubercle at the junction of the first and second brachials, the body 

 "f tin- anima] at the synarthrial tubercles bein<; 1 i mm. in diameter. The third brachial is 

 approximately triangular, not quite so long as broad, with strongly concave sides. The fourth 

 and fifth brachials form a syzygial pair which is approximately triangular (both elements being 

 triangular, the hypozygal slightly longer than the epizygal) and about as long as broad: the 

 following brachials are similar to the third, gradually becoming slightly longer in proportion 

 their width. and the shorter side becoming slightly longer. None of the arms are preserved 

 yond the tenth brachial. 



occur on the various arms as follows: left posterior, brachials 44-5, 7 4- S, 

 10 + 1 1 ; left anterior, 4+5. 7 -f 8, io-f 11; anterior, 4 + 5. 7 + 8: right anterior 4 - 5, 

 ~ T ii: right posterior, 3 -1-4, 6 + 7, 9 + 10. 



The width of the arm at the base of the first brachial is 4 mm., at the first syzygy 

 mm., and at the third syzygy 5.5 mm. 



'1 he surface of the disk is more or less mutilated and concealed. The disk resembles 



that ol Atelecrinus, and is comparatively small and compact; its ventral surface reaches the 



height ot the of the ninth brachial. The ventral surface of the disk is in the form of a 



high rounded dome, beginnihg to curve inward at about the fifth brachial; from this point 



the ambulacra, which reach the arms at about the ninth brachial, are supperted upon high 



narrow bridges as in Gephyrocrinus, Thalassocrinus and Ptilocrinus. Lip to the- height of the 



:neral surface of the disk the pinnules are connected with it by webs or thin sheets of 



•isome, resembling the thicker sheets which support the brachial ambulacra in their passage 



to die arms. A strip ot thii ome extends downward interradially to the union of the 



first brachials, just above which it bears a cluster of about a dozen rounded calcareous plates. 



Just above the union of the first brachials are deep oval pits, whether blind or not cannot be 



determined without dissection; similar but somewhat larger pits occur just bevond the distal 



angles of each first brachial, on either side of each syzygy, and at the base of each pinnule 



The sculpture of the syzygial face. in this species is unique. Laterally and dorsally the 



itral canal is bounded by a high ridge of t ite width; from this ridge there extends to 



I margin of the joint face in the dorsoventral line another ridge which at first is 



• id as the ridge from which it springs, bui outwardly gradually broadens slightly, 



imilar ridgi ad ontward, one from end of the latero-dorsal rid iboul the 



