BOTRYLLIDiE. 597 



Fam. BOTRYLLIDiE. 



Animals compound, fixed, adhering by their sides in a 

 greater or less number, so as to resemble a single complex 

 animal. Each individual with distinct branchial and anal 

 orifices, and not connected by any internal union. Ovipa- 

 rous and gemmiparous. 



Sub-fam. BOTRYLLIN^E. 



Individuals united in systems around common excretory 

 cavities. Thoracic and abdominal regions not distinct, the 

 viscera being pushed forward on the side of the branchial 

 cavity, and forming with the thorax an ovoid mass. 



Genus botryllus, Gaertner. 



Test irregular, gelatinous, .formed of numerous systems 

 arranged in simple stars. Individuals horizontal, with the 

 vent far from the branchial orifice ; branchial orifices simple, 

 ranged round a common cloaca. 



Syn. Alcyonium, Auct. Polycyclus, Lam. Pyura, 

 Blainv. 



Ex. B. polycyclus, Savigny, pi. 134, fig. 1. Individual, 

 B. polycyclus, fig. 1, a. 



In this genus the tests of the animals are fixed together, 

 forming a common mass in which the animals are imbedded 

 in one or more groups or systems, but the individuals are 

 not connected by any internal union. The species vary 

 considerably in form and colour, being purple, yellow, blue, 

 grey, or green. 



VOL. II. I 11 



