THE NAUTILUS. 



61 



tically in the sandy bottom with the body whorl only exposed. 

 I do not know whether they buried themselves or the shifting 

 sands did. 



The Unio complanatus collected varies greatly with the locality. 

 Those from the Rahway River are cleaner than those from 

 Notch Brook and are not so ventricose. The anterior end is 

 more elongate than the brook form, and the sexes are hardly 

 distinguishable. The Notch Brook females are much shorter 

 than the males and more truncated, as the following measure- 

 ments of the largest specimens show: 



Having collected only in two localities this year I obtained 

 the following species. From Branch Brook Park, Newark, 

 Planorbis parvus and Planorbis antrosus. These species were 

 found in shallow water near the shore. 



At Halcyon Park (Bloomfield) in a small pond, if it can be 

 called such, I found large Planorbis trivolvis, the largest of which 

 measures 25 mm. ; also Pseudosuccinea columella and a species of 

 Ancylus which I have not identified. I believe the shells in this 

 pond came with the water-lilies that are growing there. 



