IN THE MUD OF THE LEVANT. 49 



one projection at each corner.* Viewing the 

 lateral aspect of Triceratium Favus, under a low 

 magnifying power, it is often scarcely distin- 

 guishable from the lateral view of Zygoceros 

 Rhombus, and of short frustules of Biddulphia 

 aurita, both of which are well known to occur 

 in the peculiar chains, so common amongst the 

 Diatomacese. I cannot help thinking, that when 

 our knowledge of Triceratium and its analogues 

 is more extended, we shall find some of them 

 also occurring in chains. Systephania, a disc 

 closely resembling Coscinodiscus lineatus in other 

 respects, has two of these lateral projections, 

 which, according to Dr. Bailey, do connect distinct 

 individuals in their young state ; an exact analogue 

 of what we find amongst theDiatomacese.f In pass- 

 ing from Triceratium Favus to Zygoceros, we lose 

 the beautiful reticulated structure, but this returns 

 in Biddulphia pulchella, so that it does not affect 

 the argument. The mode of their development, 

 also, so far as our imperfect knowledge of it goes, 

 appears to favour the idea of a connection be- 



* Amongst some objects from the Phillippine Islands, sent 

 to me by Dr. Bailey, is a form identical with Triceratium 

 Favus in every respect, except that it is quadrangular. 



t Dr. Bailey on some new localities of fossil and recent 

 Infusoria. Silliman's Journal. Vol. 48. 



