FROM THE ZONE OF AMMONITES ANGULATUS. 



13 



The mineralization of the specimen gives the appearance of a columella in the elongated 

 calice, but there is really no such a structure. 



4. Thecosmtlia rugosa, Laube} PI. II, figs. 1 — 6. 



The corallum springs from a small base, divides soon, and the branches are covered 

 with an exceedingly strong epitheca marked vi^ith thick folds. 



The calices, one or more in number, are either nearly round, or are irregularly 

 distorted. They are deep, and the septa are stout, straight, and not very unequal. 

 They number from thirty-four to thirty-six. 



The diameter of a tolerably regular calice is ^'^^ths inch, and the length of a distorted 

 calice ^oths inch. The height of the corallum is about an inch. 



Locality. The Sutton Stone. In the Collection of Charles Moore, Esq., F.G.S., 

 Bath. 



M. Laube's description of the species from the St. Cassian beds is simple and accurate. 

 His small Thecosmilia has a strong epitheca, veith constrictions and swellings, and its 

 cahces are now and then fissiparous. His plate gives the idea of there being more septa ; 

 and this is the only distinction which can be made between the St. Cassian and the British 

 species. 



5. Thecosmilia Brodiei, Duncan. PI. X, figs. 1, 2, 3, 4. 



The corallum is rather short ; the corallites are cylindrical and large in relation to 

 their height, and they appear to divide near together, so that regular calices are rare. 

 The epitheca is stout and complete, being marked with slight constrictions. 

 The calicular margin is sharp, and the calices are deep. 



The septa are numerous, and the large primary and secondary septa are equal and 

 very dentate. The tertiary septa are very much smaller than the secondary, are not 

 dentate, but are long; and the septa of the fourth and fifth orders are very small. 



Diameter of the calices -ih.^ inch. 



Locality. Brocastle. In the Collection of Charles Moore, Esq., F.G.S., Bath. 

 The extraordinary development of the dentate first and second cycles of septa 

 characterise the species. 



' Laube, ' Die Fauna der Schichten von St. Cassian,' 1 Abtheil. 



