130 College of Forestry 
TABLE NO. 6. 
wo 
Hasirat TYPES. 1 2 
SraTion NUMBER. I Ill, poe | = | XENON | oNeNOle | XX XIX, XL. 
Acella haldemani.......++-- |} 3] 1 5 
Pseudosuccinea columelia....|..-\--+- ic 
Pseudosuccinea columella, 5 i: BPA Metensss 
chalybea..... ++ --2222+0° 
Lymnaea stagnalis lilliane..|.. alle ie 
Planorbis campanulatus.....|-- SEZ llerie = 
Planorbis trivolvis........--|++-\|+s> hte eo a ec A ae ath eienepotated 
Planorbis hirsutus........-- ened Ve Ue) Vso eee Vata aM see al Vt. 
Planorbis exacwous......-++|+-++|- |r? 
Planorbis partus.......-+-- JES |ESA Alter exer ate oats 
Ancylus fuscus......++++-+ I PSeaAl wat ll eeonsears |e eee epecees leas 
Ancylus parallelus.....----\-3-)+3° bere es! eae 
Physa ancillaria warrenianda. | Falla egos c 
Physa gyTind.....---+++-5° Waar ees 
Valvata bicarinata normalis.|..-\-+-|+-+-° ite sree 
Bythinia tentaculata........|.--|---ferreefortt yy Nee eed bons, Ocoee 147 
Amnicola lustrica......--+- \ eco |e tao aco rae 40 | FRc. wall conte acl eee 
Motalea ss. « sys Gy HOS Ay Sale Zaltatr 4 18 174| 4 
| | |e | | 
Tn many pond-hily habitats, a number of mollusks live 
attached to the submerged leaves of Scirpus, Dianthera and 
the stems of Nymphea, Castala, and floating Potamogeton- 
Acella in one habitat (Station XXXI, 1, B) was partial to 
the submerged leaves of Scirpus smithi: (Fig. 39, 1). At 
other stations Galba catascoprum and Planorbis campanulatus 
were observed on the submerged portions of Dianthera (Fig. 
39,2). The latter species (Planorbis) often attaches itself 
to the stems of Nymphea, ( vastalia and Potamogeton natans. 
The leaves of the latter plant also served as a resting place 
for Acella at one station (X, B). No estimates of the num- 
ber of individuals in these latter habitats have been made. 
It will be noted that in many habitats one or more species 
dominate (these may be called principal species) ; thus a 
boulder association may include 30 Galba and 3 Gonobasis, 
or 15 Goniobasis and no Galba. Thus we have communities 
