ORDER I CRINOIDEA—LARVIFORMIA 135 
Haplocrinus, Steining. (Fig. 236). B five, R five, unequal. Three of the 
radials composed of two pieces, of which 
the uppermost or superradial is the 
larger, and bears an articular facet for 
the attachment of the arms. Arms 
small, simple, uniserial, resting within 
deep grooves formed along the sides of 
the orals. Orals large, pentagonal, and 
laterally in contact; the posterior one 
pierced by a small anal opening. Mouth 
subtegminal ; column composed of thin 
joints. Not uncommon in the Middle Fic. 236. 
Devonian of the Eifel and Nassau: Haplocrinus mespiliformis, Goldf. Devonian ; 
Gerolstein, Eifel. «@, Calyx seen from one side; 
sparse in the Upper Devonian of North +, Seen from above; ¢, Seen from below ; d, Diagram 
A . of calyx; 0, Basals ; 7, the three unsymmetrical plates 
merica. situated between basals and radials; 7, Radials; 
br, First arm-ossicle ; 0, Orals. 

Family 2. Allagecrinidae. Etheridge and Carpenter. 
Calyx very small. Basals five, radials fire, of wregular form 
and size. Some of the radials axillary and supporting two arms ; 
others truncate and supporting but one arm ; their articular facets 
provided with transverse ridges and large muscle plates. Upper 
Sub-Carboniferous ; Europe and North America. 
Allagecrinus, KE. and C. B completely anchylosed in the 
adult, and the suture lines between the orals also disappear- 
ing with age. Stem largest next to the calyx, rapidly 
tapering downward. Sub-Carboniferous ; Great Britain and 
North America. 
Family 3. Pisocrinidae. Angelin. 
Jalyx small, globose or cup-shaped, and composed of heavy 
plates. Basals three to five, radials five, very unequal, the vight 
posterior one compound. Inferradial completely roofed over by 
the lateral flanges of the superradial and right antero-lateral 
radial. Arms simple, wiiserial, and composed of long, cylindrical 
joints. Silurian and Devonian. 
Pisocrinus, de Kon. (Fig. 237, 4). SB five, unequal, 
forming a triangle. Only the large anterior radial, and the 
left posterior resting upon the basals ; the superradial of the 
Fic. 237. right posterior ray, and the right antero-lateral radial, being 
Ree een aaelifer, supported by the upper angle of the inferradial; the latter 
a, Perfect. ‘specimen, not in contact with the anal tube. Articular facets of the 
ven from ae’ say, Tadials impressed between vertical partitions formed by the 
seen from one side ; 
[cst eae ee nia lateral margins of the plates. Tegmen rarely preserved ; 
fe er veniam: but, as observed by Wachsmuth in P. pilulc, consisting of 
rerolstein, ifel. a, <P te 5 2 = 
Calyx seen from one five large symmetrical orals, above which rises a_ long, 
side: 7 F “Sel 
side; 0, From below. "i. narrow, anal tube. Arms long, and composed of extremely 
elongate, heavy, cylindrical ossicles. Silurian ; Gottland, Dudley, England, and 
North America (Niagara Group). 

