228 Dr. A. Giinther on Two new 



the pinnate insertion of septal pairs became more and more 

 modified to a cyclical system of insertion. The author points 

 out in favour of this view how the untoward circumstances 

 for coral existence which prevailed in Europe during the 

 Upper Carboniferous, Permian, Triassic, and Liassic ages 

 may have given a widespread impulse towards the carrying 

 out and confirmation of the main evolutionary change as 

 above stated. The change, however, has been ever since in 

 progress. The author traces its constant working within the 

 family of Astr»ida3, its influence on Eupsammidte and Oculi- 

 nidai, and so on. 



There is therefore, in the author's opinion, no greater 

 fallacy than the idea that some universal change took place 

 amongst Madreporaria at the end of Palaeozoic time and before 

 the mid-Triassic era. One and the same line of evolution 

 may be detected making its way in the group of Madrepo- 

 raria. Precocity in advance was shown by the Palajozoic 

 Cyathophyllids ; hence the high difterentiation of Astraiids, 

 Eupsammids, and Fungids as early as Mesozoic ages. On 

 the other hand, the Palaeozoic Za})hrentidsand their descendants 

 in Mesozoic times were remarkably backward in advance, and 

 it is among their recent representatives that primitive struc- 

 tures and forms are chiefly upheld. Naturally retrogression 

 and atavism is shown in various degree in all families, in 

 none more so than in the Turbinolids, the family most closely 

 allied with the ancient Zaphrentids. 



The author draws up a new classificatory system of Madre- 

 poraria into a number of independent families of equal rank. 

 These are based on the study of skeletal structures, known 

 facts of anatomy, and phylogenetic relationships. She 

 arranges the families, according to the lines of descent demon- 

 strated in the present paper, as follows : — 



Zaphrentoidean B'mnilies : Zaphrentidaj, Amphiastrgeidai, 

 Turbinolidas, Stylinidae, Oculinidse, Pocilloporida3, Madre- 

 poridaj, Poritid^e. 



CyatJiophylloidean Families : Cyathophyllida3, Astrasidge, 

 Fungidai, Eupsammidai. 



XXXI. — Descriptions of Two new Species of Snakes from 

 Sarawak. By Dr. A. GuNTHER. 



In a collection of Snakes which I received recently from 

 Mr. C. Hose there were two species which appear to be 

 undescribed. 



