VII.] ACICULARIA. 167 



Acicularia Schencki, has been recorded from Martinique, 

 Guadeloupe, Brazil, and a few other places. 



The genus Acicularia was founded by D'Archiac for certain 

 minute calcareous spicules found in the Eocene sands (Calcaire 

 Grossier) of the Paris basin. D'Archiac describes one species, 

 Acicularia pavantina, which he defines as follows : — " Polypier 

 aciculaire, ^largi, et 16gferement comprimd k sa partie superieure, 

 qui est echancrde au milieu. Surface couverte de petits pores 

 simples, nombreux, disposes irr^gulierement^" The same species 

 is figured also in Michelin's Iconographie Zoophytologique, and 

 described as an organism of which the exact zoological position 

 is uncertain''. After these fossils had been placed in various 

 divisions of the animal kingdom, Carpenter' described several 

 specimens as portions of foraminifera. Finally, Munier-Chalmas 

 removed Acicularia to the plant kingdom, and "with rare 

 divination" placed the genus among the Acetabularieae. The 

 history of our knowledge of the true nature of Acicularia 

 is of unusual interest. Some of the specimens of this genus 

 figured in Carpenter's monograph have the form of imperfect 

 long and narrow bodies tapering to a point at one end and broad 

 at the other (fig. 33, F and G) ; they are joined together laterally 

 and pitted with numerous small cavities. From the resemblance 

 of such specimens to a fragment of the terminal fertile disc of the 

 recent Acetabularias, Munier-Chalmas referred the fossils to this 

 ty3)e of algae. In the living species which were then known 

 the radiating chambers of the disc contained loose sporangia, 

 without any calcareous matrix filling the cavity of the chambers. 

 In the fossil Acicularias, on the other hand, the manner of 

 preservation of the pitted calcareous spicules pointed to the 

 occurrence of sporangia embedded in cavities in a calcareous 

 matrix. Subsequent to Munier-Chalmas' somewhat daring 

 conclusions as to the relation of Acicularia to Acetahularia, 

 Solms-Laubach found tha,t the species originally described by 

 Mobius as Acetahularia Schencki from Guadeloupe presented 

 exactly those characters in which the fossil specimens differ 



' D'Arehiao (43) p. 386, PI. xxv. fig. 8. 

 ■• Miohelin (40) p. 176, PI. xlvj. fig. 14. 

 3 Carpenter (62) p. 137, PI. xi. figs. 27-32. 



