44 THALLOPHYTES, BRYINAE. 



at these spots is not apparent ; there are no emergences, such as hairs for 

 example, which could have passed through the deposited matter. The 

 branching is always in regular dichotomies, which commence in each case 

 at the upper end of one of the cell-like members while still young. 



Munier Chalmas l , in a recent publication, has sought to identify Peni- 

 cillus with the genus Ovulites, Lamk., which is common in the sands of the 

 Eocene formation, especially round Paris, and was formerly classed with 

 Foraminiferae. Though further and extended investigation may be neces- 

 sary to establish the justness of this comparison, as will be shown in the 

 remarks which follow, yet it must be regarded as a very happy and inviting 

 suggestion. 



The calcareous shells as preserved in Ovulites are ovoid or fusiform, 

 and pierced by a large hole at both extremities ; sometimes there are two 

 holes beside one another at one extremity. The shells are everywhere very 

 thin and fragile ; their surface, which appears smooth to the unaided eye, is 

 seen under high magnifying power to be broken by a large number of 

 steep-sided dot-like pores, which are surrounded by fine lines inclosing 

 polygonal spaces. Putting aside the thinness of the shell and the irregular 

 distribution of the pores, we have here a structure which might also be very 

 well left behind by a plant like Cymopolia-, especially if the calcification in 

 it was continued only to the wall of the central tube ; for the wall-like sides 

 of the pores, thin as they are, favour the view that they represent the lumina 

 of lateral members which have themselves disappeared. Munier Chalmas 

 indeed, and Stcinmann- also, are of opinion that there were lateral members 

 of the kind in Penicillus also, answering to the vacant spaces in the calca- 

 reous shell. But this is a mistake. Moreover, these spaces in Penicillus 

 have not the sharply defined boundaries of those of Ovulites, their shape is 

 more irregular, and several of them often run together into irregular figures. 

 There is also no appearance in Penicillus of the reticulated design charac- 

 teristic of the shell of Ovulites. The occurrence of members with two axile 

 perforations at the upper extremity certainly shows that the thallus of Peni- 

 cillus was dichotomously branched ; but these holes must also be found in 

 plants of the nature of Cymopolia, if the bridge of membrane lying in the 

 bifurcation of the branches and terminating the lower member is calcified. 

 If it is not, the two round holes will be confluent into one ovoid hole, as in 

 Penicillus. From all this I should conclude that we have in Ovulites mem- 

 bers of a calcareous Alga, which may be compared with the group which 

 we are considering, but whose position in the system cannot be finally 

 determined without further investigation. 



Of the incrusted Florideae the only forms at present known to exist 



1 Munier Chalmas (2). 2 Steinmann (2). 



