BRTOZOA 261 



A. dichotoma (Verrill) (Fig. 427). Colony 5 cm. or more high and 

 white in color, repeatedly foiking, a short, dark-brown segment being 

 at the base of each fork; zooids crowded together spirally in groups of 

 6 to 12 each : New Jersey northwards, on algae, rocks, etc., in shallow 

 Avater; often common. 



Family 4. VALKERIIDAE. 



Colony branching and erect or recumbent and creeping; tentacles 

 8 in number, 2 of which are bent outAvards towards the side and 6 are 

 erect; zooecia contracted below: 1 genus. 



Valkeria Fleming. With the characters of the family: 4 species. 



Fig. 427 Fig. 428 Fig. 429 



Fig. 427 — Amathia dichotoma (Osburn). Fig. 428 — Valkeria uca (Osburn) 

 Fig. 429 — PaludiceUa ehrenheryi. 



V. uva (L.) (Fig. 428). Colony composed of delicate jointed tubes, 

 which creep over seaweed, hydroids, or shells, or may stand erect to a 

 height of 5 to 10 cm. giving oft' paired branches ; zooids in thick clusters, 

 which are principally at the base of the branches and on them: from 

 New Jersey northwards, in shallow water; Europe. 



Family 5. PALUDICELLIDAE.* 



Colony with a horn-like or membranous cuticula and composed of 

 delicate, jointed, branching, recumbent or partly erect tubes, which creep 

 over stones and sticks in slow streams and fresh-water ponds : 2 genera. 



Key to the genera of Paludicellidae : 



tti Zooids recumbent, not rising from stolons 1. Paludicella 



a. Zooids erect, rising from stolons 2. Pottsiella . 



1. Paludicella Gervais. Colony consists of series of club-shaped 

 zooids placed end to end and separated from one another by partitions ; 

 opening lateral; branches usually paired; no statoblasts present but 

 hibemaeula or winter buds which persist when the rest of the colony 

 has died: 1 species. 



P. ehrenbergi van Beneden (Fig. 429). Colony recumbent or partly 

 erect ; length of zooid 2 mm. ; number of tentacles about 16 : cosmopolitan. 



* See "Observations on Budding in Paludicella and Some Other Bryozoa," by 

 C. B. Davenport, Bull. Mus. Comp. Zool., Vol. 22, 1890. 



