THE NAUTILUS. 



Anodontce occurred with their usual abundance and perplexing 

 variety so characteristic of the inland lakes of Michigan. Possibly, 

 owing to the unprotected character of the shore near Charlevoix, 

 but few were found in Lake Michigan. A. footlana Lea, however, 

 was found at Fisherman's Island near Charlevoix and also at St. 

 James' Harbor, Beaver Island, where .4. subcylindmcea Lea and 

 ferussaciana Lea also occurred. But it was among the Corbiculidae 

 that the most interesting finds of the expedition were made. Both 

 species and individuals were exceedingly abundant. Indeed, there 

 can be no doubt that the smaller Pisidia form one of the most im- 

 portant portions of the food of the whitefish. The Sphaeria were 

 most abundant in the inland waters where S. simile Say and stria- 

 tiniim Lam. were found in profusion nearly everywhere. S. rhom- 

 boideum Say and the beautiful little S. rosaceum Pme. also occurred 

 in one of the smaller lakes. A fine, new species, about the size of 

 S. occldentale Pme. was dredged from 25 metres off Grand Traverse 

 Bay. A larger form not yet satisfactorily determined was brought 

 up from a lesser depth off the south end of Beaver Island. The 

 Pisidia are now in the hands of Dr. V. Sterki, who has kindly con- 

 sented to examine and determine them, so that the entire list can- 

 not be yet given. But I am enabled to state that there are, at least, 

 twelve species represented, of which seven are new to the State, in- 

 cluding four species new to science. At High Island Pisidia were 

 particularly abundant. A fine triangular form, as large as P. vir- 

 yinicum Bgt., proves to be the P. idahoense Eoper. At the same 

 place, Dr. Sterki's recently-described species, P. punctatttm, also 

 occurred. A most interesting find was that of a form which Dr. 

 Sterki informs me cannot be distinguished from the P. mi Hum Held., 

 of Europe. This, I believe, is the first instance in which a species 

 of this family has been proved to be an inhabitant of both conti- 

 nents. The other species found were P. variabile Pme., nbditinn 

 Hald., compressum Pme.,rotundatum Pme. and ventricostmi Pme. In 

 all, ninety-three species of mollusca were obtained, of which eleven 

 species and three varieties were new to the fauna of the State, one 

 species new to this country, and five species new to science. 



ISAAC LEA DEPARTMENT. 



[Conducted in the interest of the Isaac I,ea Couchological Chapter of the Agassiz 

 Association by its General Secretary, Mrs. M. Burton Williamson.] 



The Isaac Lea Conchological Chapter of the Agassiz Association is 



