70 munroe: consumption of acids 



become phylogenetically fixed as definite plates. Any change 

 in the mechanics of an animal with a spicular skeleton we should 

 suppose would be immediately accompanied by either (1) a dis- 

 solution of an existing plate or plates, or (2) the sudden union 

 of two or more plates. 



In the urchins the presence of the anal opening in the anal area 

 normally occupied by the apical ("sur-anal") plate has resulted 

 in preventing that plate from assembling and has kept it in most 

 cases as a mass of small disconnected plates (cf. Vidensk. Meddel. 

 fra den naturahist. Forening i Kobenhavn, 1911, p. 27) which 

 collectively represent the primitive apical plate, the potential 

 homologue of the crinoid stem. Were the anal opening somewhere 

 else we should undoubtedly find a single plate covering what is 

 now the anal area in the urchins just as it does in the crinoids. 



The sudden union of several plates is seen in such crinoids as 

 possess three instead of five basals; the three basals collectively 

 are the equivalent of the five collectively; but five have been 

 reduced to three not by a fusion after formation, but by a fusion 

 before formation, really a redivision of the basal-forming area, if 

 it may be thus expressed, resulting from changed mechanical 

 conditions at the time of skeleton formation. In the same way 

 it seems to me that the radials, originally double, have become 

 single through the operation of mechanical factors upon a prim- 

 itively diffuse spicular skeleton which in most cases has not 

 affected the succeeding plates. 



CHEMICAL STATISTICS.— The consumption of the commoner 

 acids in the United States. Charles E. Munroe. 



On November 10, 1904, I had the honor of calling the attention 

 of the members of the Washington Chemical Society to the fact 

 that as the statistics for chemical manufactures are now being 

 collected and presented by the Bureau of the Census they could 

 be used in solving many problems of interest and value, among 

 them that of ascertaining the principal industries in which a given 

 material has been used and the extent of its use. The results of 

 such a research should prove to be not only of general scientific 

 and economic interest, but also of special value in legislation and 



