102 THE NAUTILUS. 



and re-examined, proving to be an undescribed species of Crassatel- 

 lites from a region where none had been reported hitherto. 



CRASSATELLITES BRASILIENSIS n. sp. 



Shell solid, small for the genus, yellowish-white, covered with a 

 thin brownish periostracum ; valves ovate, slightly squarish behind, 

 rapidly descending and rounded in front, with pointed, slightly flat- 

 tened beaks, sculptured with a few (5 to 10) low concentric waves 

 beyond which the disk is smooth, or concentrically striated with 

 some very obscure, fine, radial lines near the anterior base ; lunule 

 narrow, elongate, bounded by an obscure sulcus inside of which the 

 area is excavated ; escutcheon similar but much larger; basal margin 

 minutely crenulate within, hinge normal, the resilium immersed but 

 rather short and wide ; muscular impressions well defined. Height 

 27.5 : length 36 ; diameter 15 mm., some specimens being propor- 

 tionately a little shorter. 



The posterior end is obscurely truncate, but in some specimens 

 slightly rostrate. On the whole, the species has much the aspect 

 externally of a smoothish Astarte. The bottom temperature where 

 dredged was 57 Fahr. The beaks are usually a little behind the 

 anterior third of the valves. 



SHELL COLLECTING ON THE MISSISSIPPI. 

 BY FRANK C. BAKER. 



For a number of years it has been the custom of the Chicago 

 Academy of Sciences to have a Field-day some time during the 

 month of July and to spend the day investigating some notable or 

 particularly interesting locality, from a zoological, botanical or geo- 

 logical standpoint. These excursions are not only attended by mem- 

 bers of the Academy, but by the faculties and students of the Chicago 

 University, the Northwestern University and kindred scholastic 

 bodies. 



Saturday, July 12th, was chosen as the field-day for 1902, which 

 dawned bright and pleasant. About one hundred and fifty people, 

 including many of the charming " co-eds " from the Zoological De- 

 partment of the Chicago University, met at the Chicago, Milwaukee 

 and St. Paul depot, from which the special train left at eight o'clock 



