248 



BRYOZOA 



Family 3. PEDICELLINIDAE. 



Colonial marine Entoprocta in which the zooids rise from a creeping, 

 branching stolon; the stalk is long and separated from 

 the calyx by a diaphragm: 2 genera. 



Pedicellina Sars. With the characters of the fam- 

 ily : 6 species, 3 in Long Island Sound. 



P. cernua (Pallas) (P. nutans Dalyell; P. americana 

 Leidy) (Fig. 405). Calyx cup-shaped with 12 to 24 

 tentacles; stalk yellowish-red in color, with or without 

 spines on stalk and calyx and tapering towards the top: 

 on shells and algae in shallow water; Atlantic coast, from 

 Labrador to Florida; Europe; often common. 



Fig. 405 



PediccUina 



cernua 



(altered from 



Osbiirn). 



1, mouth 



2, anus 



3, stomach. 



Class 2. ECTOPROCTA. 



Bryozoa living in large colonies, in which the anus is outside the 

 lophophore and this structure Avith the tentacles can be retracted into 

 the zooecium (Fig. 406). The body cav- 

 ity is an extensive space which is lined 

 throughout by a peritoneum consisting 

 either of a single layer of cells or thin 

 layers of an irregular cellular parenchy- 

 ma. In certain species the body cavities 

 of the zooids communicate with one an- 

 other. The digestive tract is a wide 

 ciliated U-shaped tube, the aboral por- 

 tion of which is the sac-shaped stomach. 

 Joining the aboral end of the latter or- 

 gan with the base of the body cavity is 

 a mesenterial strand called the funiculus. 

 The animals are hermaphroditic, the 

 gonads developing in the peritoneum, the 

 testes usually on the funiculus and the 

 ovaries on the lateral walls. The ova and 

 sperm, except in the fresh-water species, 

 fall into the body cavity, where fertili- 

 zation takes place. The eggs develop 

 in the body cavity up to the larval stage in certain species, when 

 the young animals reach the outside either through a birth opening 

 or as the result of the disintegration of the parent. In other forms the 

 fertilized eggs pass into special outgrowths of the body wall called ooecia 

 or ovieells (Fig. 414,1) and develop there. In the Phylactolcemata the 



Fig. 406 — Diagram of an ectoproct 

 (Chilostomid). 

 A, a retracted animal ; B, an 

 extended animal (Delage et H6- 

 rouard). 1, lophophore ; 2, mouth ; 

 o, anus ; 4, operculum ; 5, retrac- 

 tile muscle ; 6, funiculus ; 7, di- 

 gestive tract ; 8, zooecium. 



