HAMBACH STRUCTURE & CLASSIFICATION OF PENTREMITES. 54I 



original specimen of this description and figure is also now in the 

 collection of the Washington University, but it does not show 

 anything of the remarkable structure represented in the figure. 

 It is a specimen from Spergen Hill, Ind., and a number of speci- 

 mens from the same locality as well as those from Greencastle, 

 Ind., also a small variety found in the upper layers of the Chester 

 or Kaskaskia limestone, frequently present the same appear- 

 ance — which, however, is due to the oolitic character of the rock 

 in which they are imbedded. This induced me to call them 

 " ovulum-like bodies." Now, if Mr. Carpenter could explain 

 the nature of these small ovulum-like bodies, or the origin of 

 the so-called Oolitic limestone, he at once would know what kind 

 of ovum I had reference to, and would probably know also 

 whether it were partly or wholly hatched. On the other hand, 

 he would greatly assist the science of Lithology, forasmuch as I 

 know this question is not yet satisfactorily explained ; as to the 

 Bryozo£E, I found they are fragments belonging to the genera 

 Fe7iestella^ Polypora^ and others, also common in this formation. 

 Besides these two different forms covering the summit and 

 more or less the ambulacral furrows of the Pentremites which 

 were first described by Dr. Shumard and subsequently by other 

 authors (and now again by Mr. Carpenter, certainly without any 

 improvement in the description), there is still another form men- 

 tioned by Dr. Shumard* as roofing in the summit of the calyx, 

 but not, as misrepresented by Mr. Carpenter,, is this cone-shaped 

 integument observed on P. Norwoodi ; however, I do not mean 

 Fig. 2. to say that this and similar other species were 



never in the possession of such an organ. The 

 only species on which Dr. Shumard observed the 

 the same, was a specimen of P. sulcatus Roemer 

 (see Fig. 2). It is so seldom found preserved, 

 that, in thirty years' collecting, during which 

 Pentremites sul- ^ime I Collected at One locality more than 6,000 

 tu1Sar^''°rrm'il Specimens, I found only two specimens having 

 on the summit. ^j^jg conc-shaped body preserved. As already 

 stated. Dr. Shumard was the first one who made mention of it, 

 but his description is insufficient and incorrect ; so that the true 



* Transactions of the Academy of Science of St. Louis, vol. i., 1856-60, p. 243-4. At this 

 place Dr. Shumard also confounds Elaacrinus Verneuilii Roemer with Pentremites. 



