608 Contributions to Invertebrate Palaeontology. 



middle of the callus which coats the body of the volution within the aperture. 

 Umbilical chink small. Surface of the shell marked by fine, nearly vertical, 

 even striae or lines. Apex apparently mamillated. 



Formation and Locality. — In the higher beds of the Coal Mea- 

 sures, near Marietta, Ohio. The specimen figured is in the collec- 

 tion of the School of Mines, Columbia College. 



Pupa vetusta and P. Vermilion en sis are both associated in the 

 material in which they are found with small helicoid shells {Zonites 

 and Davjsonella), also pulmoniferous in character ; but the Ohio 

 shell up to the present time is not known to have any such asso- 

 ciate ; on the contrary, like the first individuals of P. vetusta dis- 

 covered, it is accompanied in one of the layers in Avhich it occurs, 

 by immense numbers of what appears to be a species of Spirorbis, 

 which is so abundant that small hand specimens from which two of 

 the Anthracopupas were obtained appear to be nearly half composed 

 of these shells. The form of the shell is similar to most species of 

 the genus, and has a diameter of nearly one line. Although it 

 occurs packed together in such immense numbers in the rock it has 

 one surface generally more or less flattened as though for attach- 

 ment to some foreign body, and has I presume during life been 

 attached to marine plants, from which it has fallen as they were 

 decomposed, and thus been amassed on the muddy bottom. 



ANNELIDA. 



Spirorbis aiitliracosia. 



Plate XVI, figs. 18 and 19. 



Spirorbis anthracosia Whitf. , Am. Jour. Sci., Feb. 1881. 



Shell minute, planorbiform, composed of from one to two and a half volu- 

 tions, tube slender, and very gradually increasing in diameter, marked by 

 very fine, irregular encircling stri?e, which are often gathered into little knots 

 or points near tlie border of the open umbilicus. Lower side of the shell more 

 or less flattened as if for the attachment to some foreign substance. Diameter 

 seldom exceeding one line, generally less. 



Formation and Locality. — In the higher strata of the Coal 

 Measures, near Marietta, Ohio. 



