of the Rugosa to the living Zoanthecn. 



383 



Recently tlic Geolof^Ical Deparfcrnent of the United States 

 National A[u3euni has generously prepared for me serial 

 transverse sections of several species of Palajozoic corals *, 

 for study in connexion with certain results upon the mesen- 

 terial and septal arrangement in Madreporaria. Among these 



Transverse section throuj^h the tip of a second coralluni, taken a little 

 hit^her comparatively than the former section. The two median 

 septa are still represented by a continuous line and the lateral 

 boundaries of all the septa are partly indicated bv small oval iiiter- 

 septftl loculi, which in the actual sections are filled with transparent 

 calcite or some opaque matter. In the drawin^rs the loculi throu"-h- 

 out are represented as opaque. Within the middle and lower primary 

 interseptal spaces on the right side occur the dark lines of two new 

 secondary septa (A), but no trace of any is seen on the left side. 

 It is not unusual in modern corals for the growth of one reo-ion to be 

 slightly in advance of that in another. The interrupted line towards 

 the upper border of the figure marks the outline of the actual section. 

 In this and some of the other figures the sections represented had 

 been slightly fractured at one region or another during their prepa- 

 ration ; but in order to give somewhat of symmetry to the drawin"-s 

 I have attempted restorations of the outline, the actual boundaries 

 being indicated by the interrupted lines. 



are several specimens of LophophyUnm proliferum (McChes- 

 iiey), the species investigated by Pourtal^s. ' The fossils were 

 collected from the Coal-Measures, Springfield, 111., and the 

 preservation, even to the tip, is very perfect, while the 

 practical absence of internal vesicular tissue enables the septal 

 arrangement to be followed with every degree of certainty. 

 The preparations enable me to assert that in each case the 



* For the selection of the specimens and the supervision of the prepa- 

 ration of the sections I am indebted to Prof. C. Schuchert and Air. T. 

 Wayland Yaughau. 



