MELOCRINIDZE. 265 
Arms biserial. Dorsal cup subturbinate. . . . . . Patelliocrinus.* 
Arms uniserial; dorsal cup depressed; interbrachials 
few, longitudinally arranged). = 3 3 « 5 = = « Allocrinus. 
C. BASALS LARGE, PROBABLY THREE, ANCHYLOSED. 
a. Costals two, the first quadrangular. 
Interbrachials few. 
Dorsal cup subeylindrical ; basals and radials very large, 
distichals small; arms unknown . .. . Centrocrinus. 
Calyx Hgneagsiestnateliaser basals small, inter Perchials 
few, the first extremely large. Arms biserial and gen- 
erally branching. Slit-like Rae ae: pores at the 
sides of the ambulacral openings . . 6 6oa6. on Dolatocrinus. 
6. Costals one; pentangular. 
Otherwise resembling Dolatocrinus . . . . Gf Stereocrinus. 
Interbrachials numerous, basals forming an Svieaea cup Hadrocrinus. 
Geological and Geographical Distribution. 
Number of known species. 
(Open figures indicate American; those marked ( ), European.) 
ie | 
| ForMATION. MELOCRINIDA, 
ae 
Melocrinites. Dolatocrinites. 
& () a a“ 
BR a=] wn s i] a 
oS American. ita A Se |) eb etal | 3 WM petete ten) SEMI Pos Sy IP ee Ts tae 
| Fehr (ict josey | ioten al tel Iran Sel etre Se | crt etsiea rela a |lecseal sil | oat 
| SHS | Sh | Tee sy dee | Pid |) See ee Sy I ee ilerer ty tata asyel) aah as 
| aso ONG eee | beetle | Pees | ete lietetenl| rite ieee le cesinl| ea leon |S alias 
488 ea eS) Se lice | emia fs || sal | ee sj/filae|e|s4 
Pa | om o 3 S| oO 3 8/5 ira) |3 
Leva] ov o io} Ss = =] 2 8 
GlMlalslalalaellaloia/sa/sSialala 
Hamilton. Up. Devon. 3 (9) 8 
—) —_ j—— 
2 Up. Helderberg. | Eifel. 1(7) 5 2 
| 
o —j\-—_— — — 
> 
2 . 
Q | Oriskany. 2 
|Low. Helderberg. | Grauwacke. 2 2 (3) 
= Wenlock. 
H | Niagara. Bohemia. (3) |3(1)) (1) |5 (4)| 6 (6) | (7) | 2 
a Gotland. 
= —— | ——_ | —_ | —— 
= A 
= | Hudson River. 4 
wa — 
z 
A Trenton. Bhi 1 
Total species 95 | ft Panes ease (a) 6 || 2 | (6)|(7)} 2 | 1 
Mere lS) ~ | (3)| @) o 
| | 
* Excluding P. fulminatus and P. duplicatus, which probably belong to Mariacrinus, and P. chiastodac- 
tylus and P. pinnulatus, which are young specimens. 
34 
