G. M. Ehlers — New Species of Tetracoralla. 467 



The holotype 3 of Heterolasma patens differs from 

 Heterolasma foerstei in having a smaller nnmber of 

 lamelliform, secondary septa (32 or 34), in the much 

 greater extension of the, secondary septa toward the 

 center and in the apparent absence of low quaternary 

 septa and radiciform processes. It is possible, however, 

 that the holotype of Heterolasma patens may possess 

 radiciform processes. These, if present, are not shown 

 because the specimen is imbedded in matrix. If better 

 preserved specimens of this species are found, showing 

 Heterolasma foerstei, then the two species should be 

 combined under the name Heterolasma patens (Billings). 

 At this time, however, enough differences in structure 

 between the Anticosti and Michigan specimens are known 

 to warrant their separation as distinct species. 



The genus Heterolasma seems to represent an aberrant 

 departure from Zaphrentis. It differs from the latter 

 genus chiefly in not having the septa reach the center of 

 the* corallum. In this respect, it resembles Amplexus. 

 The genus Heterolasma is also characterized by its wide 

 tabulae and its shape, which is that of a short cone with 

 more or less horizontally extended margins. One of the 

 most distinctive characters of this genus is the difference 

 in the form of the septa. The name Heterolasma, which 

 well indicates this character, was suggested to the writer 

 by Dr. A. R. Foerste, in whose honor the writer takes 

 great pleasure in naming the genotype. 



University of Michigan, 

 Ann Arbor, Michigan. 



3 The writer is under obligations to Miss A. E. Wilson and Dr. M. Y. 

 Williams of the Canadian Geological Survey for information relating to 

 the structure and preservation of the holotype of Heterolasma patens. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistey and Physics. 



1. The Determination of Zirconium by the Phosphate 

 Method.— G. E. F. Lundell and H. B. Knowles of the U. S. 

 Bureau of Standards have rendered valuable service to mineral 

 analysis by a study of this method, originally devised by Hille- 

 brand for the determination of the minute quantities of zir- 



Am. Jour. Sci.— Fourth Series, Vol. XLVIII, No. 288.— December, 1919. 

 32 



