458 
(4). Third zone, the forest proper, containing 
Quercus macrocarpa. Mossy-cup, or Bur Oak. 
Populus tremuloides. American Aspen. 
Ostrya virginiana. Hop Hornbeam or Ironwood. 
Quercus bicolor. Swamp White Oak. 
Carya ovata. Shellbark Hickory. 
The western end of the pond is free from reeds, 1s very shallow, 
and supports the following marsh-loving plants: 
Proserpinaca palustris. Mermaid-weed. 
Ranunculus multifidus. Yellow Water-Crowfoot. 
Sium cicutefolium. Hemlock Water-Parsnip. 
Ranunculus multifidus covers the bottom of the pond every- 
where, in the deeper as well as in the shallower portions. 
The invertebrate life of this station is quite varied*. The fol- 
lowing species were observed. 
INSECTS. 
Limnotrechus marginatus. Water-strider. 
Corixa interrupta. Water-boatman. 
Notonecta undulata. Back-swimmer. 
Zattha fluminea. Water-bug.f 
Libellula basalis. Dragonfly (adult). 
Hydroporus undulatus. Diving beetle. 
CRUSTACEA. 
Cambarus blandingt acutus. Crawfish. 
MOLLUSKS. 
Molluscan life was quite abundant in the pond. Lymn@a was 
found plentifully on dead pieces of cattails and reeds, many having 
hibernated on the stems of the reeds, two to four inches above the 
water; other individuals were found in the water attached to the 
submerged base of the cattails. The Lymnzas were not found in 
open patches of water where no cattails grew. Planorbis occupied 
the same habitat as Lymn@a. Physa was rare in this area. Suc- 
cinea was plentiful on the stems of cattails near the water. Seg- 
*The vertebrate life of stations VII-X VII, is listed on page 468. 
+This water-bug preys upon mollusks. Mr. B. F. Isely, of Tonkawa, Okla- 
homa, has observed it feeding upon Physa in an aquarium, large numbers of the 
snail being eaten. 
