192 



THE CRINOIDEA 



syzygy ; IIBr x united to lax by articulation ; arms isotomous, incorporated 

 in cup at least up to IIBr 3 ; iBr few and irregular ; the upper columnals 

 widen gradually, and, with the proximale, form a cone passing into the 

 cup (Fig. XVII. 5, 6). Guettardicrinus, d'Orbigny (1840), Upper Jurassic, 

 differs from Apiocrinus only in the union of IIBrj to lax by close suture, 

 the incorporation of a greater number of IIBr in the cup, and the presence 



21 3 



PIG. CXIII. 



Calamoerinus Diomedae. 1, the crown and proximal portion of the stem from the right 

 posterior interradrus, x . 2, the root, nat. size. 3, the interior of the basal circlet, from 

 above, showing the anchylosed sutures (S) and the axial cords (ax) radiating from the central 

 chambered organ, x {. (After Agassiz.) 



of more iBr ; it is the acme of this line of development. Acrochordocrinus, 

 Trautschold (1859 ; synn. Cyclocrinus, d'Orb. non Eichw. ; Mespilocriniis, 

 Quenst. non de Kon.), Jurassic and Lower Cretaceous ; columnals only. 

 Calamoerinus, A. Agassi/ (1890,-92), 392-782 fathoms, Galapagos Is. and B. 

 of Panama (Fig. CXIII.). Patina distinct, owing to restriction of facet to 

 f width of R ; BB tend to be fused ; RR laterally united by ligament ; 

 r. and 1. post. RR slightly longer than the others. I~Br l united to R by 



