390 TWENTIETH REPORT ON THE STATE CABINET. 



rence to Modiolopsis, till more satisfactory relations shall be found. The 

 description of "radiating ridges on the anterior slope," should probably 

 be on the posterior slope, which is thus marked. 



I shall take the liberty, in this connexion, of commenting upon some of 

 the species described in this memoir, in the order of their arrangement, 



Favosites venustus ? Hall sp., Pal. N. Y., Vol. ii, pa. 120, pi. xxxiv, f. la-i. 



The Favosites venustus is a massive coral, occurring in hemispheric 

 forms, not diflScult of recognition in its ordinary condition ; and no one 

 has a right to mistake "an expanded incrusting coral, adapting itself to 

 the inequalities of the underlying surface," for this species. A comparison 

 with Thecostegites hemisphcericus of li(EMER, a species having all the cha- 

 racters of my Genus Callopora, is equally wide of the characters of 

 Favosites venusta. I am compelled to say, but without asperity, that such 

 comparisons do our science no good or credit. 



The Chicago specimen, referred to by Prof. Winchell, has been 

 obligingly loaned to me by him for examination, and I regard it as the 

 upper part of an irregularly hemispheric mass, which adheres to the stone 

 by the cell-apertures of the unequal upper surface, while the lower part 

 has been broken off or dissolved, leaving short portions of the tubes which 

 are presented from the lower side. The specimen is too obscure for positive 

 determination, but is probably the F. venusta. 



I have not critically examined the species of Cladopora described, 

 except the C. reticulata. The condition of these fossils, and of the greater 

 part of the Corals and Bryozoa in the Magnesian limestones of Wisconsin 

 and Illinois, renders their determination difficult and often unsatisfactory, 

 and naturalists might not always be able to agree regarding specific identity 

 or difference. 



Ischadites tesselatus, W. and M., page 85, plate ii, fig. 3. 



This species is identical in form and characters with Receptaculites 

 infundilulus, Report of Progress Greol. Survey of Wisconsin, p. 16. 1861. 



Actinocrinus obpyramidalis , W. and M. page 87, plate ii, fig. 4. 



This species I regard as identical with Melocrinus verneuilii == Turhino- 

 crinus verneuilii of Troost. It has not the structure of an Actinocrinus. 

 This opinion is fortified by an examination of the original specimen in the 

 collection of Prof. Marcy. 



Megistocrinus (Owen and Shumard), page 87. 

 The forms referred to this genus by W. and M. are not of the type of 

 Megistocrinus of Owen and Shumard, but are of the Genus Saccocri- 

 Nus (Hall). If the division of the Genus Actinocrinus shall be recog- 

 nized, then Megistocrinus will be adopted for forms like the typical 

 species of the genus, of which there are several in the carboniferous lime- 

 stones. The generic name Saccocrinus was proposed for a form quite 



