Edwards,] 260 [May 17, 



The form I wish at the present time to describe, is of a brackish or 

 perhaps salt water habit, as it was found in the living state associated 

 with both brackish and salt water species, and in a part of the marsh 

 at times open to the water of the ocean. Although I bestow a name 

 upon it,. I wish it to be distinctly understood that I do not therefore 

 claim that it is a new species, but apply the name to it merely to 

 distinguish it, so that hereafter as it is better known it may be re- 

 ferred to and correctly placed. At the same time, I must say that I 

 am strongly of opinion that it will be found on careful examination to 

 be as good a species as most of those at the present time included in 

 the genus. It is allied to Pleurosigma Baltica, of Ehrenberg; that is 

 to say, the markings upon the valve are of the same character; being 

 so arranged as to make it appear as if the valve were covered with 

 darkish lines running at right angles to each other, and in general, 

 parallel and transverse, to the median line. In outline it is closely 

 allied to P. speciosum of W. Snjith, but is much shorter on S. V., in 

 proportion to its width, than that species. The characters of this 

 form are briefly as follows : 



Pleurosigma robustum. 



F. V. linear. S. V. linear-lanceolate, strongly obtuse, flexure very 

 slight, ends blunt, sides parallel for about one-third of the length. 



Length, .115 m. m. Width of valve, .03 m. m. Markings appar- 

 ently consisting of parallel lines crossing each other at right angles, 

 14 in. .001 m. m. 



Habitat, brackish or salt water. 



Locality, Coney Island, Long Island, New York, Sept. 27, 1862. 



P. S. Since the above was written I have found the same form, 

 although still not common, and mixed with various others, growing in 

 the form of a fawn-colored stain upon the sand of the sea shore at 

 Coney Island. Several beautiful forms were obtained by washing 

 the sand thus colored, and they would seem, for the most part, to be 

 identical with those Dr. Donkin obtained in the same way some years 

 since on the coast of Northumberland, England. 



Section of Entomology. May 24, 1871. 



Mr. P. S. Sprague in the chair. Nine members present. 



Mr. Sanborn described a simple method of preparing the 

 skins of caterpillars for the collection. First puncture the 



