70 



" Pasceolus globosus." 



" Description. — Sub-globular from one to two inches in diameter ; 

 surface markings principally hexagonal, and about two lines in diameter. 



Locality and Formation. — Trenton limestone, City ol Ottawa, where it 

 is found in certain quarries in great numbers, usually flattened or pressed 

 into a hemispherical shape. 



Collector. — E. Billings." 



In the Palaeozoic Fossils, vol. i, p. 390, I have, in reconsidering the 

 characters of the genus, stated that these fossils have " one or more 

 circular apertures," but pointed out that in neither of the two species 

 could they be clearly detected. Shortly after the pubhcation of that 

 work, I was informed that Messrs. Verrill and Niles had read a paper on 

 the subject before the Boston Natural History Society. This paper had 

 escaped my attention, otherwise I should have alluded to the fact that they 

 first noticed the affinity between Pasceolus and Cyclocrinus. The 

 following are their remarks : — 



" Mr. A. E. Verrill exhibited specimens of Pasceolus Halli Billings, * 

 which occur in the same formation with Beatrieea at Ellis Bay, Anticosti. 



" This fossil was described by Mr. Billings as an Ascidian, but some of 

 the specimens collected by the late expedition from Cambridge showed 

 that the exterior was formed by a shell of considerable thickness, com- 

 posed of small hexagonal and pentagonal plates or prisms, having the 

 outer surface marked with raised radiating lines. Moreover some of 

 the specimens had the lateral openings well preserved, and surrounded 

 by six plates differing in form from the rest. Mr. Verrill had, there- 

 fore, considered it as a Cystidean. It also agrees with other species of 

 this group in form and appearance. 



" Mr. W. H. Niles, having recently made a more complete study of this 

 fossil, was invited by Mr. Verrill to express his opinion upon its relation to 

 the other Cystldeans. 



" Mr. Niles remarked that he had so far studied the specimens exhibited 

 as to be convinced that Mr. Verrill was correct in his belief that they 

 were true Cystideans. The species had been described by Bilhngs under 

 the name of Pasceolus Halli, but the genus had been previously described 

 by Eichwald under the name of Cyelocrhiites. The genus belongs to 

 the family Sphceronitidce. 



" Mr. Billings had not been alone in his belief that this family had Asci- 

 dian affinities.! M. Koenig considered the Cystidians as Ascidian Mollus- 

 ca, and so far as regards this family, was supported by McCoy. The fea-s 

 turos mentioned by Mr, Verrill entirely preclude the idea of these fossils 

 being the casts of the interior of Ascidians. The same kind of covering 



• Canadian Geological Survey. Report for 1853 — '56, p. 342, 



t Mr. Niles is quite mistaken ia supposing that I ever believed in the "Ascidian affi- 

 nities " of the SplKcronitidcE. I was the first to point out the occurrence of that family 

 in the palaeozoic rocks of America. I discovered and described the genera Comarocys- 

 dtex, Amys;dalocystites, and Malocystites. In all that I have written on the subject I 

 cannot find a single remark from which it could be supposed that I ever entertained 

 such an idea. 



