IN THE MUD OF THE LEVANT. 47 



chalk. Though not distinctly concamerated, there 

 is generally some constriction to be observed at 

 each turn of the spire, — a rudimentary approxi- 

 mation to the septa of the higher forms. The 

 construction of the lip in fig. 37 shows an approxi- 

 mation to the model which nature has followed in 

 the Peneroplis, fig. 32. 



Fig. 33 represents a beautiful species of Tex- 

 tillaria,with very distinct foramina, — a genus which 

 is of great geological interest, as constituting so 

 large a portion of the Chalk rocks. 



Fig. 39 is an example of the curious genus 

 Lagena. I have also observed numerous speci- 

 mens of a closely allied species which occurs on 

 our own shores — Lagena globosa — and to which 

 1 shall have to refer again. 



Associated with these Polythalamian corals there 

 are also found, in the Levant mud, numerous frag- 

 ments of minute forms of Flustra and other allied 

 Corallines. 



I have also met with some examples of another 

 class of microscopic organisms — the Siliceous 



