SYNOPSIS OF GENERA. 



l.\ in 



Family, Lepadidje. 

 Genus STROBILEPIS, nov. gen. 



Diagnosis. Capitulum composed of 

 four vertical ranges of plates, having in 

 general a trihedral form, but varying 

 greatly in contour and size. Each plate 

 is closely articulated to, and sometimes 

 overlapping the next preceding The 

 anterior extremity is terminated by a 

 relatively large, circular, conical plate 

 against the sides of which the first plate in each vertical range lies. In the 

 type species, two of the four vertical ranges of plates are of about the same 

 size, one consists of a few very small plates and the fourth is modified into a 

 series of spines which appear to be articulated to one another at their liases 

 and to lie opposite the range of small plates. Plates calcareous and relatively 

 thick. Surface ornamented by fine concentric, often obsolete wrinkles of 

 growth, and low radiating furrows and ridges, and entirely covered with minute 

 punctse, 



Genus TURRILEPAS, Woodward. 1S65. 



1865. Tarrilepas, Woodward. Quart. Journ. Geol. Society. 



1872. Plumulites, Barrande. Syst. Sil. Boheoie, vol. i. suppl. 



1875. Plumulites, Hall and Whitfield. Geol. Surv. Ohio, Palaeontology, vol. ii. 



1S76. Plumulites, C. P. Rcemer. Lethasa palteozoica. 



1882. Plumulites, Clarke. Amer. Journ. Science 



1882. Plumulites, Whitfield. Ann. New York Acad. Sciences. 



1881. Plumulites, Zittbl. Sitzungsber. d. math.-phys. Classe 'I. I-. bayer. Ak.nl. d. Wiss. 



1SS5. Plumulites, Zittel. Handb. d. Paleeontologie. 



Diagnosis. Elongate cone-shaped bodies, composed of from 

 four to six vertical ranges of scale-like plates, which are sub- 

 triangular in general outline and are covered with strong, some- 

 what elevated concentric lines. The plates of the middle range 

 are distinguished from those of the lateral ranges by their more 

 convex surface and median carina. (zittel.) 



Turrilepas Wrightianus. 



