APPENDIX. 423 



lorica is of a cubical form and cellulose, the lateral surfaces 

 being radiated, the angles assuming various conditions. In 

 this creature the angles of the lorica are sometimes very 

 obtuse, and the sides of it straight ; in others they are 

 elongated, in the form of little horns, and the sides very 

 much sloped out. The lateral surfaces are very similar to 

 the head-piece of a Bothriocephalus. Found living in 

 the waters of the Cattegat, and in a fossil state in the 

 chalk marl of Oran and Greece. Diameter 1 -860th to 

 l-430th. 



A few days before Dr. Ehrenberg sent part of his work 

 to the press, he discovered a second species of this genus 

 in the chalk marl of Greece, which he states should be 

 named (734) A. parallela, as the lateral surfaces of the 

 lorica are marked by parallel rows of cells. 



Genus CEBATONEIS belongs to the tribe Bacillaria, 

 section Naviculaceae. Its members are free, and possess 

 a simple prismatic bivalved siliceous lorica, with two 

 central opposed openings, whose solid edge is bounded by 

 two diverging longitudinal furrows, which appear to pass 

 through the horns of the lorica. In consequence of self- 

 division being complete, no chain-like masses are formed 

 by the members of this family, though they may be found 

 in pairs, or solitary. 



735. CERATONEIS closterium. Setaceous and lunate in 

 form, having two very long horns, twice the length of the 

 body. The form of this creature is like that of Closterium 

 setaceum. The ova are of a brownish-green colour, but 

 the long delicate horns are colourless. The lorica is 

 smooth, and the motion is easily seen, as it is very lively. 

 Found abundantly, along with Closterium setaceum, in 

 the sea near Cuxhaven and Wismar. Length 1 -290th to 

 1 -220th; body, without the horns, ] -1150th. 



736. CEBATONEIS fasciola. Linear, lanceolate, and 

 shaped like the letter S, the horns being shorter than the 



