428 APPENDIX. 



viewed from the lateral surface lanceolate, with the extremi- 

 ties constricted and obtuse, surface marked with large 

 and distinct granular lines, becoming obliterated in the 

 middle of the body. Found living, in sea water, at 

 Cuxhaven. Size l-720th ; striae to l-96th of a line. 



752. ACHNANTHES pctchypus. Wands striated, twice as 

 broad as long, or ovate, each slightly bent in the middle ; 

 back and apex rounded; pedicle thick and short. Breadth 

 of wand 1 -1730th. This species was discovered by Dr. 

 Montague, upon some conferva obtained at Callao (Peru), 

 which he named Confervae allantoides. Young specimens 

 of Achnanthes subsessilis are very similar to the present 

 species, which has seldom more than three, never more 

 than four joints ; Dr. Montague gives only two. 



753. ACTINOCYCLUS biternarius. Partitions not present, 

 disc having six minutely punctated rays. This species is 

 found in the fossil condition in the chalk marl of Oran and 

 Caltanisetta, in Sicily, and alive, in sea water, near the 

 island of Tjorn. The fossil state is that in which it was 

 first discovered, and it created considerable surprise when 

 it was found soon after in the ooze of the sea. Locomotion, 

 or organs for affecting it, have not been seen. From 

 A. senarius it is distinguished by the absence of the in- 

 ternal partitions. Diameter 1-1 000th to 1 -580th. 



754. ACTINOCYCLUS senarius. (1838.) Found fossil, 

 very abundantly, in the chalk marl of Oran, Caltanisetta, 

 and Greece ; alive at Cuxhaven, Christiana, and Tjb'rn. 

 Diameter 1-1 150th to l-430th. 



755. ACTINOCYCLUS septennarius. Partitions absent, 

 disc having seven finely punctated rays. Found fossil in 

 the chalk marl of Oran, Caltanisetta, and Zante ; living, in 

 the Cattegat. Diameter I -1060th to l-430th. 



756. ACTINOCYCLUS octonarius. Found fossil in the 

 chalk marl of Caltanisetta and Oran ; living, in the 

 Cattegat. 



