VII.] OVULITES. 161 



Penicillus. 



The recent genus Penicillus is one of those algae formerly 

 included among animals. Fig. 33, O, has been copied from a 

 drawing of a species of Penicillus given by Lamouroux^ under 

 the generic name of Nesea in his treatise on the genera of 

 Polyps published in 1821. He describes the genus as a brush- 

 like Polyp with a simple stem. 



The thallus consists of a stout stem terminating in a 

 brush-like tuft of fine dichotomously-branched filaments. The 

 apical branches are divided by regular constrictions into short 

 oval or rod-like segments which may be encrusted with car- 

 bonate of lime. A few of the segments from the terminal tuffc 

 of a recent Penicillus are shown in fig. 36, E. Each of these 

 calcareous segments has the form of an oval shell perforated at 

 each end, and the wall is pierced by numerous fine canals. 

 Penicillus is represented by about 10 recent species, which with 

 one exception live in tropical seas. 



The recognition of Penicillus, or a very similar type, in a 

 fossil condition is due to Munier-Chalmas^ This keen observer 

 has rendered great service to palaeobotany by directing attention 

 to the calcareous algae in the Paris basin beds, and by proving 

 that many of the fossils from these Tertiary deposits have 

 been erroneously included by previous writers among the 

 Foraminifera*. It is greatly to be desired that Prof Munier- 

 Chalmas may soon publish a monograph on the fossil Siphoneous 

 forms of which he possesses a unique collection. 



Ovulites. Figs. 33, K, L, and 35, F. 



In his Natural History of Invertebrate Animals, Lamarck v 

 described some small oval bodies from the Calcaire Grossier 

 (Eocene) of the Paris basin under the name of Ovulites. He 



1 Lamouroux (21) PI. xxv. fig. 5, p. 23. 



2 Munier-Chalmas (79). 



' For references to genera of calcareous algae previously referred to 

 Poraminifera, vide Sherborn (93). 



8. 11 



