(4ö) 



It' we compare the dorscxl re,f>ion in Petnnny/oii and in Acaiitliias, 

 it is evident that tliis reiiion is strong'ly reduced in the hitter ; 

 notwithstanding this, the same part of the whole myotome dielongs 

 in botli cases to the dorsal region. If this be true in general, it 

 seems to me, that the reduction of the dorsal region is the principal 

 moment which has led to the folding of the doi'sal part of the 

 myotome. 



In figures IV and V the position of the rib, in relation to the 

 myotome, is indicated i)y a crossed line. The rib is located in the 

 intersegmental tissue thai divides the dorsal from the lateral part 

 of the m3'otome. The junction of the ril» with the skeleton, lies a 

 little caudally in respect to the knee of the myotome ; the rib itself 

 is turned to the caudal end of the body concordant witli the caudal 

 inclination of the myotome. In a transverse section, three successive 

 ribs are cut through. 



Geology. — ''On the direction and the startincj iwint of the diluvial 

 ice motion over the Xetherlands." By Prof. Euo. Dubois. 

 (Communicated by Prof. J. M. \an Bkmmelkn). 



Referring to the ''Beschrijving van eenige nieiuve (/rondhoriiu/en,'' V, 

 by Dr. .1. Lokié, recently published in the "Verhandelingen der 

 Koninklijke Akademie van Wetensciiappen, 2'^^ Sectie, Deel 10, N". 5", 

 to which, on p. 20 and 21, the author has added a criti({ue of some 

 conclusions in my communication to the Academie: "The (/('oiixjical 

 structure of the Hondsrwj in IJrenthe and the oritjin of that ride/e" 

 (Proceedings of the meeting of Saturday, .June 28, 1902, Vol. V, 

 p. 93 sqq.), I beg leave to make the following remarks. 



The critique of that eminent student of the geology of the Nether- 

 lands is based on such an incorrect and incomplete statement of 

 my conclusions and of the facts, that the reader cannot but regard 

 those conclusions as being of a rash character, which in fact they 

 have not. 



Indeed, having said that he does well agree with my oi»inion 

 regarding the structure of the Hondsrug, Dr. Lokié continues as 

 follows ') : 



"Another case it is with a particularity mentioned on p. 4 and 

 5". (This refers to 12 lines on p. 96 and 97 of the Proceedings.) 

 "In pit XLI there was found a boulder of quartzite, having a 

 diameter of 0.35 M., cleft into two j.ieces, in such a manner 



1) This quotation has been translated from the Dutch of Dr. Lorié by me. 



