116 BE. J. CHAPMAN ON A CLASSIFICATION OF CRINOIDS. 
latter round and smooth, expanding at the base. Arms pinnulated, slightly branched, or 
simple: 1-plated. 
Fam. 27. Apiocrinide (Typ. gen. (i) Calyx large: Apiocrinus, Jurassic, Cretaceous; Mil- 
lericrinus, Liassic to Lower Cretaceous; (ii) Calyx small ; Bourgetticrinus, Jurassic to Eocene ; 
Rhizocrinus, Cainozoic and Existing ; Bathycrinus, Recent). 
Group 2.—TENUICINCTA : 
Body-plates of uniform but comparatively thin texture. 
§ 1. Carinata :—Calyx small, elevated, composed of few plates, each bearing on its 
surface a median ridge. Arms 5, widely separated at base, branching, with short pinnulæ. 
Fam. 28. Hyocrinide : (Typ. gen. Hyocrinus, Recent ; Plicatocrinus (?), Jurassic). 
§ 2. Truncata :—Stemless ; attached by base of calyx; the latter composed of a few 
closely united plates. Arms, simple, short, in living forms pinnulated. 
Fam. 29. Holopide (Typ. gen. Holopus, Cretaceous (?), Cainozoic (?), Living, Cotylederma 
(2), Liassic). 

APPENDIX. 
RETIOCINCTA : 
Body-plates and arm-plates of semi-calcareous, reticulated texture. 
§ 1. Costata:—Stemless. Calyx compysed of united, semi-calcareous plates, éach with 
strong median-rib. Arms 5, bifurcating, widely separated at base. 
Fam. 30. Saccocomide (Typ. genus Saccocoma, Jurassic). More or less closely related 
(perhaps belonging) to the Ophiuride. 
RECAPITULATION. 
I. EMEDULLATA : 
1. Amplicincta : 
. Proclinata (e.¢. Cheirocrinus). 
. Attenuata (e.g. Pisocrinus ; Hy- 
bocrinus). 
3. Spatiosa (e.g. Platycrinus). 
4. Pinnigera (e.g. (Poteriocrinus). 
5. Disjuncta e.g. Marsupites). 
b 
to 
Multicincta : 
Squamosa (e.g. Ichthyocrinus). 
. Copulata (e.g. Melocrinus ; Eu- 
calyptocrinus). 
. Ornata (e. g. Actinocrinus ; 
Glyptocrinus). 
. Opulenta (e.g. Polypeltes). 
. Mutica (e.g. Uintacrinus). 
roe 
O9 
a RE 

(The families omitted.) 
II. FISTULATA : 
1. Ramosa (e.g. Cyathocrinus). 
2. Foliata (e.g. Crotalocrinus). 
3. Fimbriata (e.g. Cupressocrinus). 
4. Quadrata (e.g. Gasterocoma). 
II]. CANALICULATA : 
1. Crassicincta : 
. Frondosa (e.g. Pentacrinus). 
. Vagata (e.g. Antedon). 
. Florifera (e.g. Encrinus). 
. Coadunata (e.g. Eugeniacrinus). 
. Conformata (e.g. Apiocrinus ; 
Bourgetticrinus ; Rhizocrinus.) 
me OO be 
or 
2. Tenuicincta : 
1. Carinata (e.g. Hyocrinus). 
2. Truncata (e.g. Holopus). 

