ORDER V CRINOIDEA—ARTICULATA 169 
Fragmentary stems occur notably in the Alps in great profusion, but calices 
are rare. 
Guettardocrinus, VOrb.. Differs from the preceding in having costals im- 
movably united with interbrachials. Solitary species: (. dilatus, VOrb. 
Upper Jura. 
Millericrinus, VOrb. Closely allied to Apiocrinus, but articular facets of 
radials and brachials more strongly developed. Base occasionally with five 
minute 7B, which are coalesced with the top stem-joint (centrodorsal) ; the 
latter extended laterally, and resting against the outer faces of the B. 
Column more or less sharply pentagonal, with the angles interradially 
directed. Lias to Lower Cretaceous. 
Acrochordocrinus, Trautsch. Jura and Lower Cretaceous. 
Calamocrinus, Ag. Recent; Galapagos Islands. (Cf. Literature, p. 124.) 
Family 3. Bourgueticrinidae. de Loriol. 
Dorsal cup small, pyriform, with shallow body-cavity, and composed of a centro- 
dorsal, five basals, five radials, and one to two costals. Tegmen (in recent forms) cori- 
accous, and with mouth surrounded by five orals. Arms five, thin, uniserial, and 
bearing very long pinnules. Stem giving off numerous cirri; composed of heavy dice- 
box-shaped joints, both faces of which are provided with elevated transverse ridges, and 
deep ligamentous fossae. Jura to Recent. 
Bourgueticrinus, VOrb. (Fig. 282). Centrodorsal unusually large, as wide 
as the calyx at its greatest width, and wider than across the basals. 2 

Fic. 282. 
Bourgueticrinus ellipti- 4. 98 
cus, Mill. White Chalk ; Fic. 283. 
Wiltshire. a, Calyx with Rhizocrinus pyriformis, Goldf. sp. Eocene; Verona. 
centrodorsal and two of a, b, Calyx from one side (nat. size and enlarged) ; 
the stem-joints (nat. size); c, Same from above, with three of the Br in place ; 
b, Ventral aspect (en- d, Median longitudinal section of calyx (nat. size) ; 
larged); ¢, Stem-joints ; e, Calyx with slightly abraded outer surface, showing 
d, Articular surface of sutnre lines between B and R; jf, Calyx with five rays, 
stem-joint; ¢, Cirrus. seen from above (enlarged); g, k, Stem-joints (nat. size). 
truncated at the upper face, and supporting very short costals. Structure of 
arms unknown. Column round; its joints almost as long as wide, the upper 
ones wider than the rest. Upper Jura to Tertiary. 
Rhizocrinus, Sars. (Conocrinus, @Orbigny non Troost), (Fig. 283). Base 
very large and elongate ; composed of five heavy plates which are more or 
less fused. & typically five, but sometimes four, six, or seven; short and 
quadrate in form. Column slender, giving off branching cirri toward the 
distal end ; composed of joints nearly three times longer than wide, and con- 
stricted in the middle. Eocene, and Recent at great depths. 
