56 ILUNOIS BIOLOGICAL MONOGRAPHS [154 



more easily infected with the glochidia, as suggested by Wilson and Clark 

 (1912:13, 14). This undulatory motion of the siphon fringes is so striking 

 that it at once attracts the attention of an observer,even if this person is 

 not interested in the study of these creatures. Its habit of burying itself 

 so deeply in the mud or sand of the bottom (four to seven inches) renders 

 this species difficult to collect, especially if the sand be packed rather hard 

 and the water is eighteen or more inches in depth, as frequently occurs. 

 This condition was found in several of the Salt Fork habitats. Gravid 

 females were also collected from other localities in October. 



34. LampsUis multiradlata (Lea). 



This handsome mussel occurs rarely at but three stations. Homer Park, 

 near Muncie, and in Middle Fork. It is common in the Big Vermilion 

 below Middle Fork. The specimens from the Salt Fork Stations are all 

 small for the species, being not over half the size of individuals from 

 White River, near Muncie, Indiana, and the hinge teeth are much weaker 

 than those from Indiana streams. This is especially true of the pseudo- 

 cardinal teeth which are narrower and more elongated than the speci- 

 mens examined from other streams. Individuals from Homer Park 

 are brilliantly rayed, grass green on a yellowish ground. Middle Fork 

 specimens are not as brilliantly rayed, the general color being yellowish 

 with scanty rays. The largest specimens collected measure as follows, 

 a specimen from Muncie, Indiana also being included for comparison: 



Length, 34; height, 22 mm. Homer Park. 



" 43 " 31mm. Middle Fork. Male 



" 69 " 55 mm. Big Vermilion. Female 



"85 "64 mm. Muncie, Ind. Female 



This species is rare in Illinois waters, judging by the few records 

 available. These indicate, however, a wide range over the State, from 

 Cook County to southern Illinois (Baker, 1906:64). Ortmann (1918:584, 

 1920:309) adopts the nzme fasciola of Rafinesque (1820) for this species, 

 stating that the original description of Rafinesque is definite enough to 

 indicate without much question a shell of the multiradiata type. If 

 this be so, then Lea's very appropriate name must give place to the 

 one used at an earlier date by Rafinesque. The species has not been 

 recorded from the Sangamon River. 



35. LampsUis anodontoides (Lea). Yellow Sand Shell. 



This fine shell, which is usually abundant throughout Illinois waters, 

 was collected at only three stations in the Big Vermilion River, all of 

 which were below the dam at Homer Park. The largest and finest in- 

 dividuals occur at Homer Park and the smallest were collected in 

 Middle Fork. Specimens from the first named station have a yel- 



