TRANSACTIONS OF SECTION C. 



725 



teeth, sonimvlinl like a shoe-last in forin, which played upon stronp:, flattened, bony 

 plates tliat covered the roof of the mouth. These, like Diploijnathm, are from the 

 |[m'0)i .-hale of Ohio, 



5, Ctniiidus 1f'(i(/iipri, Nowb., of wliich a remnrkablj' lar^e and finely preserved 

 palate tooth was exhibiteil, discovered by Mr. Frank Wagner in the Cleveland 

 tliale near the base of the ( 'iirboniferous system at (,'leveland, Ohio. 



(J. Spines of two species of Udi'stus, Leidy, from the Coal Measures of Indiana 

 and Illinois, which show distinctly the structure and mode of growth of these re- 

 markable defensive weapons. Tiiey are from 10 to 18 inches in length, very 

 massive and strong, and consist of a series of sheathing segments iirmly soldered 

 tno'ethtM', each carrying a triangular, crenulated, and enamelled denticle from 1 to 2 

 inclies in length. The spines are symmetrical and weie therefore located on the 

 median line like the spines of Trmioii, and were probably the defences of large 

 sharks or y\\\a which inhabited the inland waters of the Continent in the Carboni- 

 l-Vruiis age. 



SATURDAY, AUGUST 30. 



The Section did not meet. 



MOXBAY, SEPlEMIiER 1. 



The following Papers and Rejjort w^ere read : — ■ 



1, On the Fusdl Ecticnlatr Sponrjes constituting the Familij Dicfijofjjongidoe. 

 Bij Professor James Hall, LL.D. 



()m knowledge of these forms in America dates back to 1842, when Mr. 

 'niirad described a peculiar fossil body inider the name ITydnoceras (in the belief 

 nC its relation to Orthoceras). Subsequently in the same year another form by 

 A'anuxeni as a marine plant, and in 1802 Dawson as Alga?, and followed by J lull 

 ill IfO'f'd, who described several of the species under the name Dictyophytou ; adopt- 

 ing Vaiiuxcnrs name IJphanttcnia for other forms. 



In l"^7it .Mr. C. D. AValcott described a form refei'able to this group of fossils, 

 from the Utica State, as Cyathophycus. In 1881 Mr. K. V. Whitfield published 

 obseivations on the structure of l)ictyophyton and its allinities with certain sponges, 

 arcoiupanied by a note from Dr. J. W. l)a\^•son, on the structure of a specimen of 

 Upiianta'iiia, ii:c. (D. Walcott on the Nature of Cyathophycus.) 



Ill the same year U. V. Whitfield (with note by l)r. J. W. Dawson) described 

 two species of Dictyophyton and one of Uphantitnia. (.Uidletin of the American 

 Museum of Natural' History.) 



In ]S82, James Ilall upon Dictyophyton, Phragmodictya, and similar forms 

 with Uphantrenia. (American Association for the Advancement of Science.) 



In file luu'opean literature, the first noticeof which was observed by the writer, 

 of any fossil resembling Dictyophyton, is in Murchison's Silurian System (l8ot)), 

 where Cophinus didmn is described and figured. 



(In Morris' Catalogue this fossil is ])laced in the category of inrerfcP sedea.) 



In 184.'), Mr. Coy, in his ' Synopsis of Pritish Pakeogoric Fossils,' describes 

 Tefr(if/o)iis lhmf>iii {Receptarulitcs Danhi/i, Salter in MS.) 



Ill 1874 (4.3) Mr. Salter, in his Catalogue of the Cambrian and Silurian Fossils 

 in the Cambridge ]Museum, places Tetragonis Danhyi under the Spongidfe, 



In 1880, Dr. Ferdinand Koemer has descrilied the genera Dictyophyton and 

 I'phanfitnia (Lethea geog. Thiel, p. 120 and 128), placing them among the Algw. 

 At a later date the same author places /'etrai/onis Murchisoui, T, Danbyi, and T. 

 J^ifelensis among the Spongida). 



