April, 1901 ] 
Landacre — Sponges and Bryozoans. 
97 
known. 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- 
fied 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 each 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 
onlarge 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 saliva. L. Common Oat, escaped. W. A. Kellerman. 
61. *Wolffia braziliensis Wedd. Brazil Wolffia 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. 
