Miscellaneous. 393 



berg noticed a very interesting form among the microscopic prepara- 

 tions put up with great neatness by Mr. Topping for sale. It is found 

 in a certain kind of guano from Patagonia, and is one of the largest 

 forms. Prof. Ehrenberg has called it Hemiptychus ornatus. They are 

 isolated, comparatively very large, thin, discoid siliceous plates, which 

 exhibit radii upon their surface connected by a very delicate network, 

 after the manner of the genus Actinoptychus. These radii are like- 

 wise in the present instance raised bands, but which, commencing at 

 the margin, do not reach to the centre, but leave a broad central 

 disc, in which these bands are continued in the form of finely punc- 

 tated radial lines to the centre where a circle of teeth are visible : 

 no marginal apertures were perceptible. 



Another new genus of Polygastrica was found in some guano 

 from Patagonia brought by the Danish ship Waldemar. 



Like all the kinds of guano hitherto examined, this Patagonian 

 kind contains a considerable number of siliceous-shelled Polyga- 

 strica, together with numerous siliceous spicula of sea-sponges. 



The most interesting form is Entopyla australis, a new genus. Ex- 

 ternally it has the greatest resemblance to Tessella, but in its in- 

 ternal structure it more resembles the genus Biblarium. It forms 

 quadrangular plates, which seen from the side are rounded off above 

 and below. These quadrate tablets or boxes consist of several leaves 

 like a book, which however are firmly connected. The leaves are 

 parallel with the narrow sides and curved ; the two external leaves 

 are like the cover of a book, thicker and marked with thirty-two 

 horizontal ribs. These two outer decorated leaves resemble each 

 other in Biblarium but not in Entopyla, where one is outwardly con- 

 cave and the other outwardly convex. The concave outer leaf is 

 upon the ventral side, since it exhibits two large roundish apertures 

 at the extremities ; the opposite convex leaf has no aperture ; all the 

 intervening leaves have a large aperture in the centre, leaving only 

 a thin margin, thus forming a large continuous space in the interior 

 of these little boxes. The structure in Biblarium is similar. 



This form is not quite new, a fragment of it having been brought 

 from the Falkland Islands in the year 1843 ; it was then arranged as 

 an imperfect but characteristic form with the genus Surirella, and 

 called Surirella ? australis. It was a part of the cover of the Ento- 

 pyla, which very much resembles the shells of Surirella. 



This new guano contained — 



Polygastrica. 



Actinoptychus octonarius. Grammatophora oceanica. 

 Cocconeis oceanica. serpentina. 



Coscinodiscus subtilis. Tessella Catena. 



Entopyla australis. Synedra Gallionii ? 



Gallionella sulcata. Zygoceros Rhombus ? 

 Grammatophora angulosa. 



Phytolitharia. 

 Lithodontium furcatum. Spongolithis Clavus. 



platyodon. cenocephala. 



Fustis. 



