PLATE VII. 



UlNTACRINUS SOCIALIS. PHOTOGRAPHS DiBECT FKOM THE SPECIMENS. 



Fig. 1. The disk of specimen No. 75 (PI. IV., Fig. 1, supra) enlarged 2.2 diameters by the 

 camera. 



" 2. Part of the same disk, enlarged X 10, showing the porous nature of the calcareous 

 spicules. 



" 3. Base of specimen No. 247 (PI. V., Fig. 6, supra) enlarged x 2.2; showing theinfra- 

 basals lying completely separated from each other and from the centrale. 



" 4. Portion of arms and pinnules from specimen No. 233, natural size ; to show the 

 relative proportions of brachials in different parts of arms, or in arms of indi- 

 viduals in different stages of growth. The two large arms are from the same 

 calyx, beginning about the 25th IIIBr. The other five, of various sizes, belong 

 to as many different individuals; the smallest one, lying upon the upper part of 

 the left large arm and down along side it, being almost at the distal end. In 

 this figure the dimensions of the brachials in these arms can be compared. 



" 5. Detail of same specimen, enlarged X 2.2, to show the form and proportions of the 

 proximal free pinnules, especially the lateral sloping of the pinnulars. 



" 6. Disk of specimen No. 205, crossed and obscured by arms and pinnules of other 

 individuals, enlarged X 2.2 ; to show the form and proportions of the slender 

 pinnulars in the upper part of the arm. Here they are cemented by pressure to 

 the black disk, and by reason of the contrast in color can be well seen. 



" 7. Ventral side of arm and pinnules, enlarged X 2.2. 



" 8. Articulating surfaces of brachials, enlarged x 2.2; to show the diagonal direction 

 of the fulcral ridges. 



" 9. Syzygial surfaces of brachials, enlarged X 2.2, from arms broken off before 

 fossilization. 



