89 



This species is quite distinct from all others in almost every 

 respect and may not belong to Cyrtocer as. When compared 

 with C. dilatatum, it will be noticed that the surface is furrow- 

 ed instead of imbricated and the septa are not half as numer- 

 ous. It is not necessary to draw comparisons with other species. 



Found in the Upper Coal Measures, at Kansas City, Mis 

 souri, and now in the collection of Wm, F. E. Gurley. 



SUBKINGDOM ARTICULATA. 

 CLASS ANNELIDA. 

 ORDER TUBICOLA. 

 Family SERPULID^. 



SPIRORBIS BLAIRI, n. Sp. 



P plate V, Fig. 15, a coil attalched fo Platystoma broadheadi; 

 Fig. 14, an old specimen with the anterior end 

 prolonged upward. 



Shell sinistral and in its young state attached throughout 

 its length. Umbilicus wide. Surface marked with unequally 

 distant rings of growth. In an old specimen, as shown by 

 Figure 14, the anterior end is prolonged and stands upright. 

 The lower side of the shell, that attached to some foreign ob- 

 ject is flattened, otherwise a transverse section is circular. The 

 aperture seems, in all stages of growth, to have been directed 

 upward and when a complete coil, for attachment, had been 

 formed the further growth was in the form of a loose spiral 

 or upright tube. 



Five specimens belonging to this species have been examined 

 and the growth of the spiral in all cases, was to the left as 

 sinistral. About one coil and a quarter or less than one turn 

 and a half attached to the foreign substance. The transverse 

 ridges are closer and finer on some specimens than upon others, 

 but always more or less irregular, and sometimes quite coarse 

 and wavy, indicating lines of growth, rather than surface or- 

 namentation. 



This species is distinguished by its sinistral growth, freedom 

 towards the aparture. and surface lines of growth. 



Found in the Chouteau limestone, at Sedalia, Missouri, and 

 now in the collection of S. A. Miller. The specific name is in 

 honor of R. A. Blair, the original collector. 

 —12 



