Naviculacea.'] infusouial animalcules. 375 



rayed, with eighty-four rays ; suture of the valves single. Diameter 

 l-336th. 



Gallionella TjimpaHum. — Disc broad ; centre smooth ; slender 

 margin, minutely striate. Diameter 1-2 76th. Southern Ocean, 



G. sculpta. — Joints large, depth exceeding breadth ; lateral surface, 

 with transverse, dotted lines, (which, when the segments are con- 

 joined, become, in relation to the entire chain, longitudinal,) densely 

 Btriated, and elegantly sculptured ; two sutures about the middle, 

 with a narrow interspace. Diameter l-960th. Fossil, Oregon. 



G. (?) spiralis. — Joints small, oblique; breadth greater than depth, 

 or equal ; surface with loose, transverse, dotted lines ; chains forming 

 curves and spirals. Diameter l-2304th. Fossil, Oregon. 



G. caUigera. — Joints small, smooth, with .the habit of G. distans ; 

 breadth double the depth ; median suture single ; a double granular 

 mass enclosed within, like G. undulata. Diameter 1-1 728th. Fossil 

 in pumice. Island of Ascension. 



G. (?) coronata. — Testules Avith the habit of G. sulcata; the outside 

 of the cj'lindcr striated; margin of disc crenate; disc smooth, 

 slightly convex, with a cii'clet of granules at its centre like a croAvn 

 of pearls. Diameter 1 -864th. Fossil, sea coast of Patagonia. 



G. (?) plam. — Tcstule with tl^ habit of G. sulcata, but with the 

 disc of the valves plane, smooth, not radiated nor granular. Diameter 

 1-1 152nd. This form may possibly bo but G. sulcata, with its 

 markings destroyed (worn smooth) by igneous action. Also fossil, 

 Patagonia, in pumice, 



The following species have been found fossil : — 



G. ISfovce Mollandice, G. procera, G. tenerimtna, G. punctata, G. gihha, 

 G. Horologium, G. lineolata, G. aspenda, G. liseriata, G. punctiger, 

 and G. crenulata = Melosira crcnulata. See plate 14, f. 29. 



Melosira of Kiitzing, and Aulacoseira and Orthoseira of Mr. Thwaites, 

 are here introduced as sub-genera, from their alliance to GaUioneUa. 



Sub-genus Melosika. — The following species are derived from the 

 valuable papers of Mr. Ealfs, in the Annals of Natural History, 



"M. glolifera (Hervey.) — Frustules (testules, Ehr.) nearlj^ glo- 

 bular, with numerous striae, which are most evident on the 

 siliceous covering. Filaments affixed by a short stipes (pedicle ;) 



