128 On the chief Generic Types of Paheozoic Corals. 



tliere are no endothecal dissepiments, and the columella forms 

 a single stjliform rod, which commences at the bottom of the 

 visceral chamber, and is continued through to the floor of the 

 calice. (It may not be out of place to note here that Gya- 

 thaxonia Dalmani, E, & H., is not a true Cyatkaxonia, but has 

 1>een formed into a new genus by Lindstrom under the name 

 of Centrotus.) 



The genus Lophophylhnn commences in the Devonian, but 

 attains its maximum in the Carboniferous rocks, where it dies 

 out. All the kno'wm species are small, rarely exceeding an 

 inch or an inch and a half in length. The type of the genus 

 is L. Koninclxi^ E. & H., from the Carboniferous rocks of 

 Belgium. With the exception of a form which seems to 

 be identical with L. (Cyathopsis) eruca, M'Coy, all the ex- 

 amples figured by us (PL VIII. figs. 3-6) are new ; but we 

 reserve the description of their specific characters till another 

 occasion. 



EXPLANATION OF PLATE VIII. 



(All the figvires are drawn of the natural size.) 



Fig. 1. Diphyph/Uum conmmwn, Lonsd., ti'ansverse section of a small 

 slab, exhibiting calicular gemmation at different stages of the 

 process ; 1 a, longitudinal section of the same, showing the pro- 

 duction of young corallites and the continued growth of the 

 parent tubes. Lower Carboniferous, Bathgate, Linlithgowshire. 



Fiy. 2. Diiihyphyllum, sp., transverse section of a small slab, exhibiting 

 fissiparous development of the corallites. Lower Carboniferous, 

 Scotland. 



Fiy. 3. Lophophyllmn parvulum, Thomson & Nicholson, external aspect ; 



3 a, transverse section of the same. Lower Carboniferous, 

 Fifeshire. 



Fig. 4. Another example, from the Lower Carboniferous of Ayrshire ; 



4 A, transverse section of the same. 



Fiy. 5. Lophophyllum reticulatttm, Thomson & Nicholson, external aspect ; 



5 A, transverse section of the same. Lower Carboniferous, 

 Shiels, East Kilbride. 



Fig. 6. Lupliophyllum, sp., longitudinal section; 6a, transverse section of 

 the same. Lower Carboniferous, Shiels, East Kilbride. 



Fig. 7. Lophophyllum eriica, M'Coy (h), longitudinal section ; 7 a, ti-ans- 

 verse section of the same. Lower Carboniferous, Brockley, near 

 Lesmahagow, Lanarlishire. 



Fiys. 8-8 B belong to the next portion of this memoir, where their cha- 

 racters vrill be discussed. 



[To be continued.] 



