BRTOZOA 



247 



Key to the families of Entoprocta : 



! Solitary Entoprocta 1. LOXOSOMIDAE 



3 Colonial Entoprocta. 



&! Fresh-water Entoprocta 2. URNATELLIDAE 



& 3 Marine Entoprocta 3. PEDICELLINIDAE 



FAMILY 1. LOXOSOMIDAE. 



Solitary Entoprocta, which, however, often 

 bear young buds, with 10 to 26 tentacles, with 

 a contractile stalk at the base of which is a 

 foot gland which is of use in attaching the 

 animal and may be wanting in the adult 

 animal, and with an obliquely placed lopho- 

 phore: 3 genera. 



LOXOSOMA Keferstein. With the char- 

 acters of the family: 15 species, which are 

 usually associated with marine annelids. 



L. davenporti* Nickerson ( Fig. 403 ) . Length 

 up to 2.4 mm.; small foot gland present; tenta- 

 cles numbering from 22 to 26 ; from 

 2 to 12 buds usually present; anus 

 elevated on a cone; mammary 

 organ present in the floor of the 



vestibule to which developing embryos attach themselves to 



get nourishment: abundant in Vineyard Sound. 

 L. minuta Osburn. Body oval, .3 mm. 



long: on Phascolosoma and Phascolion on 



New England coast. 



FAMILY 2. TJRNATELLIDAE. 



Colonial, fresh-water Entoprocta, each 

 colony consisting of a few zooids, which 

 rise from a common disc; stalks long and 

 jointed and branching: 1 genus. 



URNATELLA Leidy. With the char- 

 acters of the family: 1 species. 



U. gracilisf Leidy (Fig. 404). Stalk up to 4 mm. long; calyx about 

 a tenth as long and bell-shaped; usually 2 zooids in a colony: on the 

 under side of stones in running water, in the eastern and central states. 



* See "Loxosoma davenporti," by W. S. Nickerson, Jour. Morph., Vol. 17, 

 p. 351, 1901. 



t See "On Urnatella gracilis," by C. B. Davenport, Bull. Mus. Comp. Zool., VoL 

 24, 1893. 



Fig. 403 

 Loxosoma davenporti 



(Nickerson). 



1, lophopbore ; 2. rectum 

 3, bud. 



Fig. 404 



Urnatella gracilis: 



three individuals 



(Davenport). 



