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Confluent— blended so that the line of demarcation is not 

 visible. 



Corallites — the individual tubes of a compound eorallum. 



Corallum — the calcareous skeleton of a single, or of a colo- 

 nial, coral stock. 



Corneo us — horny . 



Costse — the extrathecal extensions of the sepia of the 

 corals. 



Costals — the first brachial or arm-plates of the Crinoids 



lving between the radials and the first bifurcation of the 



arms. 

 Counter quadrants — the quadrants bounding the counter 



septum of a Tetracorallum. 

 Counter septum — the front primary septum of the Tetraco- 



ralla, opposite the cardinal septum ; the secondary septa 



are parallel to it. 

 Crenulated — notched, so as to produce series of teeth. 

 Crura — the apophyses to which the brachidiumof the Brach- 



iopods is attached. 

 Cuneate — wedge-shaped . 

 Cyathophylloid—m form like Cyathophyllum ; one of the 



Tetracoralla. 

 Cyst — a closed cavity. 



Delthyrium — the triangular fissure under the beak of the 



pedicle valve of the Brachiopoda. 

 Deltidial plates — the two plates which close the delthyrium 



in the higher Brachiopoda (Telotremata). 

 Deltidium — the single covering plate of the Delthyrium (also 



called pedicle plate). 

 Dendroid — branching after the manner of a tree. 

 Denticulate — toothed. 



Denticulation — set of denticles or small teeth. 

 Dicyclic— with two cycles of basals; applied to Crinoids. 

 Diduct or muscles— opening muscles of the Brachiopoda. 

 Discin oid — resem bling Discina . 

 Discoid — disk-like. 



