Trcminology.] 



BRYOZOA. 



335 



TERMINOLOGY. 



, post, re g. 



''^-i-^-hea.'k. 



ipediclfe v. 



l>rachialv( 



FIG. 21. o, profile view of Orthis tricenaria Conrad; b, ventral view of Orthis tricenaria Conrad; 

 c, cardinal view of Strophomena incurvata Castelnau. 



Pedicle=Ventral valve. The valve always situated on the ventral side of the 

 animal and having the foramen or pedicle opening, except in Lingula, 

 Obolella, etc., where the pedicle protrudes between the valves. When the 

 shell is cemented to foreign bodies it is always by the ventral valve. It is 

 usually the larger and deeper of the two valves in which the animal is 

 contained. It was called the "dorsal valve" by Hall, from 1847 to about 

 1861 ; since which time " ventral valve " has been used by him. " Pedicle", 

 "neural" and "receiving" valves, are synonymous terms. 



Brachial=Dorsal valve. The valve to which the arms or the calcified brachial sup- 

 ports are attached. "Ventral valve" of Hall, from 1847 to about 1861. 

 "Brachial," "haemal "and "entering" valves, are other terms more rarely 

 employed. 



post, reg., posterior region ; applies to both valves. 



beaks, the apexes of valves. 



umbo, the elevated portion of the valve immediately in front or anterior to the 

 beaks. 



c. ang., cardinal angle, or angle formed by the cardinal plane with the lateral 

 margin. 



I. a., lateral margin, or lateral area. 



ant., anterior region or margin. 



b. v., dorsal valve, p. v., ventral valve. 



c. a., cardinal area of the ventral valve. 



del., deltidium. A plate of one piece which grows over the delthyrium of the 

 Strophomenida>, and is rudimentary in some species of Orthis. This plate 

 begins, in the early larval stage of Thecidium, as a secretion from the 

 dorsal side of the body segment, and becomes anchylosed to the ventral 

 valve in the phylembryonic stage, subsequent additions being secreted by 

 the body wall and pedicle. A plate similar in appearance, the "chilidium" 



