NATURAL SCIENCES OP PHILADELPHIA. 85 



The following papers were presented for publication : 



" Description of four new species of Unionidae from Brazil, by Isaac 



Lea." "Description of fifteen new species of Uruguayan Unionida3,by 



Isaac Lea." 



And were referred to a Committee. 



Mr. Lea stated that when he made some remarks, a few weeks since, on the 

 Unionida of the United States, he gave th9 number of thetn incorrectly by an 

 inadvertence. He now desired to restate them numerically : 



Unio, 465 species. 



Margaritana, ......... 26 



Anodonta, 59 " 



550 

 To these may be added, new species in his cabinet not yet 



described, ........ 30 



580 

 And to these may be added, for North America, known to 

 inhabit Jtlexico, Honduras, Central America and 

 one in Canada, Unio, 29 



Anodonta, 8 



37 



617 

 It will be observed that we have not in North America either of the genera 

 Triquetra, (Hyria, Lam.,) Prisodon, (Castalia, Lam.,) Monocondylcea, Mycetopus, 

 yssa?idonta, or Plagiodon. They are all emphatically South American types, 

 while there does not seem to inhabit the southern half of America a single 

 species of Margaritana, (Alasmodonta, Say.) Ferussac has described a species 

 (A. incurva) as coming from South America, but there is reasonable doubt of 

 it. The Monocondylcea and Margaritana seem mutually to replace each other. 

 The Uniones and Anodontce prevail in both parts of the continent over all the 

 other genera, both as to numbers and universality of distribution. The genus 

 Mulleria, (Acostea, D'Orb.) has only been found in the tributaries of the Mag- 

 dalena in New Granada. 



Dr. Leidy called the attention of the members to a specimen of the singular 

 body, named Hyalonema mirabilis, recently presented by Dr. Ruschenberger. 

 It is the second specimen obtained within a short time for the Academy. Both 

 are from Japan. The specimen of Hyalonema exhibited, consists of a twisted 

 cord of siliceous spiculse over a foot in length, and about half an inch in 

 diameter. Twisted around it is a coriaceous membrane with wart-like eminen- 

 ces, belonging to a zoophyte, which Dr. L. regards with M. Valenciennes as 

 parasitic. The cord of siliceous spiculse, Dr. J. E. Gray supposes to be the 

 axis of the zoophyte, but Dr. L. with M. Valenciennes, views it as belonging 

 to a sponge. This latter view is apparently confirmed by a specimen of a 

 sponge, in the cabinet of the Academy, from Santa Cruz, presented by the late 

 Dr. Griffith. This sponge is an oblong oval mass, about four inches long, sur- 

 mounted at one extremity with a corona of twisted cords of siliceous spiculse 

 about two inches in length. These spiculse are very similar in structure to 

 those of the Hyalonema, mainly differing in size. 



The Publication Committee laid on the table, part 3, vol. 4, of the 

 Journal of the Academy. 

 I860.] 



