April, 1901] Landacre — Sponges and Bryozoans. 97 



l^nown. They are among the most beautiful of our lower fresh 

 water forms. The body is nearly always protected by a cyst from 

 which the anterior end of the animal projects when undisturbed and 

 into which it can be retracted. There is a larval form resembling 

 that of the worms and several other invertebrate groups, and a 

 marked metamorphosis to the adult form. The statoblasts as in the 

 sponges are of value in identification, and are formed on a strand of 

 tissue connecting the base of the animal to its cyst. The individuals 

 or Polyps increase in number by budding. 



Two species are quite common at Sandusky. Plumatella poly- 

 morpha as its name indicates is quite variable in form. The variety 

 repens was very common on the rocks on the south side of bay near 

 city. Its vine-like appearance renders it easy to identify. The 

 Polyps are borne on the ends of the branches. The vine-like cyst 

 clings closely to its support. The second species Pectinatella magni- 

 fiea was found in Black Channel on submerged fish nets. It has a 

 large spherical gelatinous base frequently eight or ten inches in 

 diameter, over which the colonies of polyps are distributed. The 

 individuals in eacli colony are arranged in the form of an aster. 

 These large colonies are striking in appearance. The larvae are quite 

 numerous and are globular in shape, and swim quite freely when 

 liberated from the parent colony. The statoblasts are found in the 

 fall as in the sponges. The process of statoblast formation and of 

 larval development were studied, but the budding of individuals to 

 enlarge the colony was not followed. The statoblasts of these ani- 

 mals seem to need to be both dried and frozen before development 

 will go on in the spring. 



ADDITIONS TO THE SANDUSKY FLORA. 

 Robert F. Griggs. 



The following plants not given in the"Sandusky Flora" have been 

 collected in Erie county. They are here given in order that those 

 possessing a copy of Professor Moseley's excellent flora of the region 

 may keep it up to date. The numbers refer to the pages of the San- 

 dusky Flora, on which the additions should be made. 



44. Avena sativa L. Common Oat, escaped. W. A. Kellerman. 

 61. *Wolffia braziliensis Wedd. Brazil Wolfifia Sandusky Bay, 

 abundant at times. R. F. Griggs. 



70. Populus balsamifera L. Tacmahac, abundant on some portions 



of Cedar Point. R. F. Griggs. 



71, Salix fragilis L. Crack "Willow, common. W. A, Kellerman 



and R, F, Griggs. 



*Previously reported as additions to State list. See Ohio Naturalist, 1 ; 15-16. 



