THE NAUTILUS. 



85 



Muscidium transversum (Say). Occurred on a sand and clay 

 bottom in water one and a half to four feet deep. The individ- 

 uals are smaller than is normal for the species. 



Pisidium abditum Haldeman. Small specimens of this species 

 were found on sand, clay, and mud bottoms, in one and a half 

 to 8 feet of water. 



Pisidium adamsi affine Sterki. Gravel bottom in 3 feet of 

 water. 



Pisidium complanatum Sterki, Gravel, sand and mud bottoms 

 in water two to 8J feet deep. 



Pisidium compression Sterki. Common in water one and a 

 half to 14 feet deep on gravel, sand, clay and mud bottoms. 



Pisidium compressum laevigatum Sterki. Mud bottom in 13 

 feet of water. 



Pisidium f err ugineum Prime. Occurs in water 3 — 8 feet deep on 

 sand, clay, or mud bottom. It resembles eastern specimens 

 from New England. 



Pisidium neglectum Sterki. A few quite small specimens were 

 collected on a mud bottom in 8J feet of water. 



Pisidium overi Sterki. A single valve of this western species 

 was found in a dredging from a mud bottom in 8 feet of water. 

 This species was first described from South Dakota and was 

 later found in Minnesota. Its occurrence in New York State 

 gives it a wide range eastward. 



Pisidium paupercidum Sterki. On sand and mud bottoms in 

 one and a half to 8 feet of water. 



Pisidium punctatum simplex Sterki. On sand and sandy clay 

 bottoms in water 1 \ to 3^ feet deep. 



Pisidium sargenti Sterki. Small individuals were collected on 

 a sand bottom in one and a half feet of water. 



Pisidium scutellatum Sterki. One of the most abundant of 

 these minute clams, occurring on gravel, sand, clay, and mud 

 bottoms in water one and a half to 13 feet deep. 



Pisidium scutellatum cristatum Sterki. More common than the 

 typical form and occurring usually with it. 



Pisidium splendidulum Sterki. Occurs on a clay bottom in 5 

 feet of water. 



Pisidium variabile Prime. Found in water 2-13 feet deep on 



