ORDERS OF RHIZOPODS— FORAMINIFERA. 17 



exceedingly delicate threads, often in large number, from the one or several 

 mouths or numerous pores of the shell. They divide and subdivide into 

 finer and finer threads, which inosculate freely where they come into con- 

 tact with one another, so as to produce an intricate net. From this condi- 

 tion, Dr. Carpenter has applied to the order the name of Eeticularia. 

 The pseudopods exhibit continual changes in their arrangement, and an 

 incessant circulation in their course. In the larger threads, two streams 

 are observed at the same time, passing in opposite directions ; in the finest 

 threads, a single stream moves outward or inward. The currents carry 

 along granules of the protoplasm, and also convey particles of food which 

 may be caught in the way of the pseudopods. 



Sea-sands contain as an important constituent the dead shells of 

 recent Foi'aminifera, though in very variable proportions. They are 

 generally most abundant in the sands of warmer latitudes, and especially 

 on shores prbfusely furnished with sea-weeds. 



Plancus,* who, according to D'Orbigny,t was the first to describe and 

 figure the shells of Foraminifei'a, counted 6000 individuals in an ounce of 

 , sand from the Adriatic. D'Orbigny estimated that there were 160,000 in 

 a gramme of selected sand from the Antilles. Schultzef gives 1,500,000 as 

 the number he found in fifteen grammes of sand from Gaeta on the coast 

 of Sicily. 



Even on the comparatively ban-en shores of New Jersey, consisting of 

 quartz sand, foraminiferous shells occur in notable quantity. In a portidn 

 scraped from the surface between tides, at Atlantic City, I estimated that 

 there were 18,700 shells to the ounce avoirdupois, all of a single species of 

 Nonionina In another sample, from Cape May, I obtained 38,400 shells to 

 the ounce, likewise of the one species. 



In sand collected by scraping up the long white lines on the bathing 

 beach at Newport, Ehode Island, occupying an indenture of the rocky 

 coast, covered with sea-weeds, foraminiferous shells were found to be much 

 more numerous, but, excepting in the case of some examples of Miliola, of 

 smaller size. In an ounce of the sand, I estimated that there were about 

 280,000 shells, of several genera and species. 



It would appear as if the deep-sea mud almost universally was mainly 



'Ariminensis de conchis minus notls. Venice 17.39. 



tForaminif^res: La Sagra, L'isle do Cuba. Paris, IHOO. Introduction, vii. 



t Organismus d. Poly thai amieu, 1854, p. L'5. 



ii KHIZ 



