no. 1 osburn : eastern pacific bryozoa — cheilostomata 5 



Glossary 



Many of the following list of terms have a special application in the 

 Bryozoa and the beginner in this group may find the definitions useful. 



Ancestrula. The primary individual of a colony, derived by metamor- 

 phosis from the free-swimming larva. 



Aperture. The orifice through which the tentacles are protruded, usu- 

 ally closed by an operculum in the Cheilostomata. 



Avicularium. A modified and usually much reduced individual of a 

 colony, without a polypide and bearing a mandible. They may be vicari- 

 ous (interzooecial) or dependent (borne on some part of a zooecium). 



Cardelles. Lateral denticles in the aperture for the attachment of the 

 operculum, often wanting in the Anasca. 



Communication pore. See Septulae and Dietellae. 



Costules. Radiating ridges forming the frontal pericyst in the Cribri- 

 morpha, they are modified marginal spines. 



Cribrimorphs. Zooecia with a costulate front (Cribrilinidae, etc.). 



Cryptocyst. A calcified inward extension from the mural rim in the 

 Anasca, often vestigial. Between it and the ectocyst is a space, the hypo- 

 stege, which serves as a hydrostatic chamber when the tentacles are ex- 

 tended and withdrawn. 



Cell. Old name for a zooecium. 



Dietellae. Small cavities around the base of the zooecial wall, in which 

 the communication pores are located. 



Distal. In Bryozoa, directed toward the oral end of the zooecium. 



Dorsal. The side of the zooecium opposite that on which the aperture 

 is located. 



Ectocyst. The chitinous membrane which covers the zooecium. 



Endocyst. The thin membrane lining the zooecium and enclosing the 

 body organs. 



Endozooecial. Referring to a type of ooecium (ovicell) formed by the 

 forward extension of the distal zooecial wall. (Compare with Hyper- 

 stomial.) 



Frontj frontal. The side of the zooecium on which the aperture is 

 located. 



Gymnocyst. The calcified area of the covering membrane in Anasca. 

 It is usually limited to the proximal end and is often vestigial or wanting. 



Gonozooecium. A modified zooecium specialized for reproduction. 



Heterozooecium. An avicularium or vibraculum, a highly modified 

 and usually much reduced individual of the colony, without polypide but 



