400 THE CANADIAN NATURALIST. [Vol. X. 



called the ectocyst, the internal the endocyst, and the horse shoe 

 shaped disk supporting the tentacles the loplw])horc — strictly the 

 bearer of the plume. The first species to which I will direct 

 your attention is the Pectlnntella magnijica of Leidy, described 

 by him in the proceedings of the Academy of Science of Phila- 

 delphia, for Nov., 1851, and defined as follows; — Ccencecium 

 massive, gelatinoid, hyaline, fixed, investing bodies. Orifices 

 arranged in irregular lobate areola3 upon the free surface. Lo- 

 phophore crescentic. Ova lenticular, with an annulus and mar- 

 ginal spines. The specimens on the table show well the hyaline 

 £jcelatinous nature of the coencecium and the arrangement of the 

 Polyps upon the surface. This is perhaps the most abundant fresh- 

 water Polyzoon in the country, being found in the quiet waters 

 about the mouths of the numerous streams, and in the small lakes. 

 It is not very abundant in Quebec, but it has been found near 

 St. Andrews, and I obtained a beautiful specimen from Lake 

 Memphremagog. I have not seen it in the neighborhood of 

 Montreal. This species prefers quiet, still waters, not too much 

 exposed, nor of large extent and subject to commotion from 

 waves. Thus I have never found it in Lake Ontario itself, 

 but always in little sheltered marshy bays, where it is found 

 encrusting logs, upright sticks, and the stems of rushes. My 

 attention was early directed to this form as it exists in extraor- 

 dinary profusion in the Desjardin canal, which leads from Bur- 

 lington Bay to my native town Dundas. The wooden sides of the 

 canal bavsin in the months of July and August are almost uni- 

 formly covered witii this magnificent species. The growth begins 

 about 1^ to 2 feet below the surface and extends in depth for 

 the same distance or even further, rarely, however, deeper than 

 six feet. The masses form extensive sheets usually a few 

 inches in thickness, or else beautiful symmetrical projections, 6-12 

 inches in thickness, which spring either from a bed of the Polyps 

 or are isolated. In the summer of 1867, during a visit of my 

 friend, the Rev. W. A. Johnson, of Weston, I showed him the 

 masses, and we agreed to subject them to examination with the 

 microscope, not having any idea as to their real nature. Judge 

 of our delight when we found the whole surface of the jelly was 

 composed of a collection of tiny animals of surpassing beauty, 

 each of which thrust out to our view in the zoophyte trough a 

 crescent-shaped crown of tentacles. Recognizing it as a Polyp 

 we were greatly exercised as to its position, presenting as it did 



