Descn'pfions of Neir Genera and Species of Fossils. 21 



species, a sub-splierionl, and in the other species, a siib-cylindi'ical 

 foi'iii. Tiiey are liollow, with a tliin envelope of imbricating plates or 

 scales. The lower ('? end has an outside indentation similar to that 

 borne by an apple for the reception of the stem, while the correspond- 

 ing part of the interior is raised into a small cone. The interior of the 

 sack appears to be lined with a very thin and delicate integument, to 

 tiie outer surface of which the scales are attached. No oi)enings of 

 any kind can be detected. 



Type: L. dickhauti. 



In tlie imbricating plates some resemblance is presented to such 

 genera of the Pal.echinid.e, as Lepidesthes^ but these fossils can 

 scarceh'^ be referred to the Echixodermata, on account of the entire 

 absence of openings, and of an}' series of plates that might be termed 

 ambulacra. The genus seems, in certain characters, to be related to 

 Pasceohis, which by some authorities is considered to be a Cystidean, 

 while others place the genus with the Protista. On account of the 

 unique characters of the specimens on which the genus is founded, I 

 have thought it advisable to describe them, provisionally, as fossils 

 with uncertain affinities. However, I have no doubt, that when these 

 characters are better undei'stood, that the genus will be the type of a 

 new family, if not indeed of a new order. 



Lepidolites dickhauti, n. sp. (Plate VII., figs. 17, \la, lib). 



All t'.ie specimens of this species examined are exceedingly flattened, 

 but their original form undoubtedly was either sub-spherical or sub- 

 pyriform, with the lower portion considerably indented. The envelope 

 of scale-like plates is ver}^ thin, being little more than one-hundredth 

 part of an inch in thickness, and appears to have been slightly flexible. 

 The plates imbricate, with the exposed margin rounded, and arranged 

 in concentric lines crossing each other in a quincuncial manner; they 

 are much smaller about the indented portion, gradual!}^ becoming 

 larger as the rows approach the upper portion. The appearance pre. 

 sented liy a specimen that is flattened verticall}', is verv like that stjle 

 of ornamental work on watch-cases called "rose engine turning," In 

 the largest plates observed, the exposed portion has a diameter that is 

 not more than one thirty-secondth of an inch. Detached plates have 

 a length that is equal to about three times the greatest breadth, and 

 are somewhat cuneiform in outline, the widest end being that one which 

 is exposed on the exterior of the sack. When the exceedingly deli- 

 cate integument lining the interior of the sack, and to the outside of 



