ACTINOCEINID^. 635 



the disk and tube quite irregular in form, size, and arrangement, almost 

 as flat as those of the cup, and growing smaller as they ajjproach the 

 arms. Column apparently stout, the axial canal large and pentangular. 



Horizon and Locality. — Upper Burlington limestone, Burlington, Iowa. 



Type in the Museum of Comparative Zoology, Cambridge. 



Teleiocrinus adolescens W and Sp. (nov. spec). 

 Plate LIX. Fig. 4. 



(?) Syn. Actiiiocrinus pcnicillus — Meek and Woktiien, 1873, Geol. Eep. Illinois, Vol. V., p. 3i2, Plate 8, 

 Fig. 3. 



Intermediate between Cadocrinus and Teleiocrinus, but nearer the latter. 

 Calyx moderately large, the height of the dorsal cup greater than the width 

 at the rim, the sides gradually rising to the top of the distichals, then curv- 

 ing abruptly outward, forming a rim, which is somewhat interrupted at the 

 interradial spaces from the palmars uj). Plates thin and slightly convex, 

 traversed by angular, well defined ridges passing from plate to plate, and 

 forming numerous triangles. The ridges are single, except between the 

 basals and radials, which are united by two or three. They meet at the 

 middle of the plates in conspicuous tubercles, w'hich are surrounded by 

 several small nodes, placed within the corners of the triangles. 



Basals of moderate size, their ridges thickened at the lower end, and 

 formed into angular processes, which project downward and rest against the 

 margins of the two upper stem joints. Eadials larger than both costals 

 together, as long as wide or a little longer ; the first costal hexagonal, 

 the second generally somewhat smaller and heptagonal. Disticlials as large 

 as the costals; both axillary, giving off from the outer side of the ray 

 an arm, which is free from above the second plate, and from the inner the 

 second axillary. This is followed by three more axillaries, of which the two 

 lower ones, respectively, support again an arm at one side, the upper two 

 arms ; there being five arms in each main division, and ten to the ray. The 

 brachials forming the rim are sharply angular on the back, and separated 

 longitudinally by deep grooves. Arms somewhat flattened, quite smooth on 

 the outer faces, but their lateral margins slightly serrated. Regular inter- 

 brachials : 1, 2, 2, 2, 1 ; the upper very narrow, and sometimes touching the 

 plates of the tegmen. Anal plate followed by 2, 3, 3, 3, and 2 plates. Inter- 

 distichal areas wide and deeply depressed, occupied by two plates, longitudi- 



