404 Transactions of the Society. 



No. 03. Coscinodiscus ocuhis-iridis Elir, x IHOO, exposure 

 10 minutes. Sliowin.iGj the ontor film covcrin}^ the hexagons, and 

 its fractured edge, l^rom MoUer's slide of Nottingham earth, in 

 balsam. 



No. G5. Navicula humerosa Breb. x 1480, exposure 10 

 minutes. Showing fracture between the costaj and through the 

 dots. From II. L. Smith's slide in very dense medium (2 '4). 



No. OC). N. serians Kiitz. x 13ii0, exposure 11 minutes. 

 Same shell as No. 57. Imt with difterent objective and focusing. 



No. 69. N. rJwmhoides Ehr. {Van HenrcJcia rhnmh. Breb.) 

 X 1300, exposure 15 minutes. Showing fractured edge. From 

 Moller's slide of Monmouth earth, in balsam. 



No. 70. Same shell, x 1900, exposure 20 minutes, and after- 

 wards intensified. 



No. 71. Same sliell, X 1110, exposure 15 minutes. Taken 

 with a diflerent objective. 



No. 79. PJeurosigma formosum W. Sm. x 1100, exposure 

 13 minutes. Same shell as No. GO, with focus slightly changed to 

 show mechanism of the raphe. From Moller's slide of Samoa sea- 

 mud, in balsam. 



No. 82. P. formosum W. Sm. x 1200, exposure 12 minutes. 

 Part of valve on one side of the median line diagonally broken, with 

 the parts still in juxtaposition. From same slide as the last. 



No, 83, P. halticum W. Sm. x llOO, exposure 13 minutes. 

 Fragment broken off parallel to midrib. From same slide as the 

 last. 



No. 84, P. halticum W, Sm, x 650, exposure 6^ minutes. 

 Fracture across the shell. From same slide as No, 79. 



No, 85. Same shell, X 1050, exposure 10 minutes. 

 ■ . No, 86. P. formosum W. Sm. x 1100, exposure 12 minutes. 

 Same shell as No, 82, 



No. 91. P, halticum W, Sm. x 1270, exposure 10 minutes. 

 Fragment from Peticolas' dry slide of diatoms from Long Island 

 Sound, 



No. 94. P, halticum W, Sm, x 1300, exposure 13 minutes. 

 Same shell as No, 85, 



No. 95. Triceratium favus Ehr. x 1300, expo.sure 12^ 

 minutes, A specimen with unusually bold marking within the 

 hexagons. From Moller's slide of sea-mud from St, Vincent's, W,I,, 

 in balsam. 



No. 9(), Stauroneis jmlchella W, Sm, (var.) x 1100, exposure 

 10 minutes, A broken shell, showing the elongated hexagons, but 

 without the stauros. From same slide as last. 



No. 98. S. indchella W, Sm, x 950, exposure 10 minutes. 

 From Moller's slide of Samoa sea-mud, in balsam. 



No. lOO. Triceratium favus Elir. x 1000, exposure 8 



