69 



INCERT^ SEDIS. 



In 1854 I collected in the Trenton Limestone at Ottawa, a number of 

 obscurely preserved sub-globular fossils, which appeared to have been 

 covered with an integument of small polygonal plates like the Cystideans 

 of the genus Sphoeronites. As there were no columns attached to or 

 associated with them, and as it could not be determined that they possessed 

 the apertures of the Cystideans, I hesitated to place them in that group. 

 In 1856 Mr. Richardson discovered another species of the same genus in 

 the Middle Silurian rocks of Anticosti. In my report for 1856 I described 

 both of these species without referring them to any precise zoological 

 station. The following is the original description ; — 



" CLASS UNCERTAIN." 



" Genus Pasceolus." 



" The above generic name is proposed for certain ovate or sub-globular 

 bodies resembling the Ischadites Kcenigi of the Silurian system, but dif- 

 fering therefrom in the form of the plate-like markings of the casts of the 

 interior, which in this genus are pentagonal or hexagonal instead of quad- 

 rangular. A specimen from Anticosti shews that the animal was inclosed 

 in a thin leather-like sack, and attached to the bottom by a short tubular 

 continuation of this external covering. Its affinities appear to be with 

 those of the Tunicata.'^ 



" Pasceolus halli." 



" Description. — Body ovate or balloon shaped, being regularly rounded 

 above and produced below into a short neck-like pedicle, which constitutes 

 the organ of attachment ; outer integument thin, its external surface cov- 

 ered with small ii-regular rounded wrinkles about ten in one line, distinctly 

 visible to the naked eye ; its interior reticulated with ridges corresponding 

 to the divisions between the plate-like markings of the cast of the inside. 

 The cast of the interior is completely covered with hexagonal or pentagonal 

 divisions, presenting the appearances of Splmronites or Favosites ; these 

 spaces are each about a quarter of a Hne in diameter at the base of the fossil, 

 but increase in size above, until at the summit they are one Hne in diameter. 

 The spaces are convex in their centres, and the interior of the mtegument 

 is fitted with concave depressions to correspond. 



One specimen was procured with the integument preserved ; it extends 

 below the base, and encloses the short pedicle as well as the body above. 

 On one side of the cast there is a small elevation about half-way between 

 the top and bottom, which appears to mark the position of an aperture in 

 the side of the animal. I beg to dedicate this species to Professor Hall. 

 Length of specimens one inch and a-half, greatest diameter about the mid- 

 dle, thirteen lines. 



Locality and Formation. — White Clifi", Gamache Bay, Middle Silurian 



Collector. — J. Richardson." 



