184 



Mr. Theodore Lyman mentioned as an instance of the 

 neglect of the study of the descriptions of our early zool- 

 ogists, the case of the Ophiura appressa (Say), which 

 by way of exclusion he had determined to be the same 

 as that recently called Ophioderma virescens (Lutken) ; 

 the last agrees perfectly well with Say's description, is 

 abundant in Florida, and differs from all other known 

 Florida or West Indian species. 



Mr. Stodder reported on the microscope slides pre- 

 sented by Mr. Samuels, Oct. 5, and referred to him for 

 examination. 



The specimens he found to be very interesting, and some of 

 them new ; especially the diatoms from the intestines of holothu- 

 rians and echini — collected for Prof. Agassiz and Mr. J. M. 

 Barnard. Many species have been ascertained to be common to 

 the Sandwich Islands and the Mediterranean ; some are common 

 to England, Nova Scotia, Boston Bay, and the Sandwich Islands ; 

 others are common to the Sandwich Islands, Zanzibar, and Flori- 

 da, — in fact, diatoms have long been known as the most cos- 

 mopolitan of organisms. 



The new species, recognized as such, by Mr. A. M. Edwards, of 

 New York, are Synedra magna, S. Pacijica, Triceratium circulare 

 (with three and four sides), T. elegans (with three and four sides), 

 and T. undatum (with three, four, and five sides). These varia- 

 tions raise the question again, whether there is any distinction be- 

 tween Triceratium and Amphitetras ; several four-sided species are 

 described by Mr. Brightwell, and the only difference between 

 T, Wilkesii and A. Wilkesii (Harvey & Bailey) is the number 

 of sides. Among the rare and recently described forms are T, 

 dubium (Bright.), Cocconeis Jimhriata (Bright.), and Biddulphia 

 reticulata (Roper). Campelodiscus striatus (Ehr.), figured by 

 Brightwell in the Journal of the Microscopical Society, is abun- 

 dant, but he is satisfied that it is distinct from Ehrenberg's spe- 

 cies, answering neither to the description nor the original figure 

 of that species ; he proposes to call it C. Brightwellii. Synedra 

 undulata (Greg.) = Toxarium undulans (Bailey), and S. Hennedy- 

 ana (Greg.), and Navicidce, are abundant. Navicula didyma 



