âI think weâve read every single book they have.â Mark chuckled. He still wasnât ready to put the children downâWill was hanging off of one hip, his hand on Markâs shoulder as he stoically looked down at Bridget, and Mabel had nuzzled into the crook of Markâs neck with a contented sigh.
Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, but are usually almost bilaterally symmetrical, hence the group name.
Diatoms are unusual in that as single celled algae they possess cell wals impregnated with silica-effectively the cell walls are made of glass. The cells are made of two halves, frustules held together by a kind of belt, called a girdle.iatom Circle slide. Such slides were especially popular in the 19th century as exhibition pieces to show of both the beauty of the diatoms and also the prowess of the slide maker. It has been said that the ideal tool for arranging diatoms is a tiger's whisker.