Descriptions of New Genera and Species of Fossils. 29 



robust, and has the prongs projecting from the sides of the branches 

 more nnmerous. 



Formation and locality : in the soft shales of the lower portion of 

 the Hudson River Group, at Covington. 



Elevation of strata about one hundred and fifty feet above low water 

 mark in the Ohio River. 



Collectors : H. E. Dickhaut, E. O. Ulrich. 



Crateripora, uov. gen. 



[Eiy.— Crater, a bowl ; pora, a pore.] 



Attached to foreign substances, usually forming small, but sometimes 

 quite large expansions, with a deep, cup-like depression in the central 

 part; the latter feature imparting to specimens of the species, much 

 resemblance to crinoid bases or roots; and composed of minute canals 

 radiating irregularly from the cup, and passing obliquely to the sur- 

 face. Spiculse not observed. 



Type : Crateripora lineata. 



This genus includes several species, which occur in circular or ex- 

 panded forms, presenting a minutely striated or pitted surface. Al- 

 though I have examined a large number of good specimens, many of 

 which were cut for examination with the microscope, we are not alto- 

 gether certain that the genus should be referred to the sponges. It 

 possesses characters entirely peculiar, and [)robably is a true Paleozoic 

 type. 



Crateripora lineata, n. sp. (Plate VII., figs. 28, 28«.) 



[Bty.— From Unea, a line.] 



Generalh^ growing parasiticall^' upon foreign bodies, but apparently 

 was sometimes free, consisting of small patches, from two to four lines 

 in diameter, usually circular, at other times with the outer margin ir- 

 regular. The cup in the center is provided with a raised margin, and 

 has a diameter one fourth that of the entire specimen. Radiating from 

 the cup are verv fine thread-like stride, the number of which is increased 

 as the margin is approached by interpolation. Upon close examination, 

 the}' prove to be elevated ridges separating the rows of canal apertures. 

 In the cup the apertures are also placed between raised lines radiating 

 in ever}- direction from the middle. From fourteen to sixteen rows 

 occupy the space of one line. Sections taken at a right angle with 

 the surface show the canals in the middle of the expansions to proceed 

 upwards from the base, and terminating in the cup, while the others 

 take an obliquely-outward course to the surface. 



