106 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



do not appear till about June and remain throughout the summer. It occurs at 

 Go Home, Parry Sound, Skerryvore, French River, Killarney, Manitoulin Island, 

 and Waubaushene. It has also been found at Brantford and Sudbury, 

 p^ Habitat. — Found in the same places as P. articulata, on the under sides of 

 stones in streams or along exposed shores, or under sticks, water-lily leaves, etc., 

 in bays and ponds. The abundance was about the same in 1911 and 1912. 



Genus Plumatella. 



Key to species. 



A^ Colony with vertical as well as horizontal branches. 



Bj Cuticula thick and brown, with a keel that broadens at the aperture. 



Free statoblasts elongated; proportions 1: 1 '53 to 1: 2*8. P. emarginata. 



Bj Cuticula thick and colorless; colony robust; zooecia in groups; keel 



absent; free statoblasts nearly circular. P. repens. 



B3 Cuticula colorless to brown; tubes elongated, often pendant; may be 



keeled and emarginate; free statoblasts nearly circular. P. fungosa. 



A2 Colony with horizontal branches only (rarely vertical). 



C^ Cuticula colorless to brown; tubes usually with a clear, longitudinal 



band; depressed and closely adherent to the substratum (usually). Free 



statoblasts nearly circular. P. appressa. 



C2 Cuticula delicate, colorless to white; mouth cone elevated, often wrinkled 



and speckled with white. Free statoblasts nearly circular. P. punctata. 



Plumatella emarginata Allman. {=princeps Kraepelin). var. emarginata. 



P*-*^ Tubes openly branched, repent, with short lateral branches, antler-like. 



Statoblasts always few, but more abundant in older colonies. Although lather 



well distributed about Georgian Bay, this form is nowhere very abundant, and the 



colonies are rather small. It is found at Go Home, Parry Sound, Skerryvore, 



French River, Killarney, Manitoulin Island, Fitzwilliam Island, Tobermory, and 



McGregor Harbor. Specimens have been collected also at Brantford. 



Habitat varied; frequently under stones along rather exposed shores, but 

 also under stones or sticks in bays or in running water. Appears June to September, 

 more abundant in July than earlier. Colonies become darker with incrustations, 

 but modifications with the season not great. More abundant in 1912 than in 1911 

 at Go Home. 



Plumatella repens (Linn.) (=P. polymorpha, var. caespitosa and repens Kraepelin). 

 This is the most variable of all the species found in Georgian Bay. The colony 

 starts from an embryo of usually two individuals, and single tubes develop, branch- 

 ing somewhat openly. At this stage it is much like P. punctata, var. prostrata. 

 Later the zooecia are found in groups, and the colony is caespitose. If the area 

 of the substratum is very limited, a dense mass, half or three-fourths of an inch 

 thick is formed with only the apertures rising free. In some cases the tubes remain 

 scattered, or are intertwined rather than bunched. It is very probable that this 

 last variation is the P. polymorpha, var. repens of Kraepelin. Intermediate stages 

 may readily be found. It is, of course, found in the same places as the more usual 



