TUNICATA 



669 



1. BoTRYLLUS Gaertner. Colony thin and crust-like and embedded 

 in a common gelatinous tunic, the individuals being in circular, stellate, 

 or elliptical gToups, in each of which they are arranged radially around 

 a common eloacal opening; incurrent opening widely separated from 

 the eloacal and near the periphery of the group; oral tentacles not 

 branched and few in number: about 24 species; principally in North 

 Atlantic and Mediterranean, in shallow water. 



B. schlosseri (Pallas) {B. gouldi Verrill) (Fig. 1,013). Colonies 

 massed thickly together on seaweed, stones, etc., forming gelatinous, 

 black or purplish incrustations sometimes 10 cm. or more in diameter, a 

 colony being made up of many groups, each group consisting of from 

 5 to 10 individuals and 3 to 6 mm. in diameter: Long Island Sound and 

 northwards; very common; Europe. 



f; .. -^ . . - ^a A 3 ^ .5 



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Fig. 1,013 — Bofryllus schlosseri. A, a colony on a seaweed containing 7 groups 

 of individuals (Gould) ; B, diagram of a single group of individuals; C. diagram of 

 two individuals of a group with the common eloacal opening, the right-hand individual 

 in sagittal section (Delage and Herouard). Explanations as in Fig. 998. 



2. BoTRYLLOlDES Milne-Edwards. Colony thin and crust-like, the 

 individual animals lying perpendicular to the surface and usually not 

 arranged in definite groups; the individuals lie along eloacal canals 

 which meet and open to the outside through a common eloacal pore: 

 over 2 dozen species. 



B. nignim Herdman. Colony up to 7 cm. in diameter, very variable 

 in color, usually purplish or blackish; individuals about 1.5 mm. long: 

 Bermuda; in shallow w^ater; common on stones and seaweed. 



Family 2. DISTOMIDAE. 



Colony thick, sometimes stalked, usually embedded in a common 

 tunic; individuals consisting of thorax and abdomen, the viscera being 

 beneath the branchial sac, which is without internal longitudinal bars 

 or folds; openings each with 6 lobes: 10 genera, with about 80 species. 



DiSTOMA Gaertner. Colony thick and fleshy, with the individuals 

 often in groups; intestine very long; branchial sac short: about 20 

 species. 



D. clarum Van Name. Colony jelly-like, transparent, 12 mm. in 

 width and half as thick; individuals lying at all angles to surface, white 



