404 AüGÜSTA RUCKEE, 



(3), V. 12, 1879] he has proved (p. 170—171) that tlie four pairs of 

 large diverticula in Op. Laniatores are glands and not besides reser- 

 voirs for food". Undoubtedl}' tlie diverticula in Koenenia are glan- 

 dulär but certainl}' not more so than any other region of the mid- 

 gut; tliis whole region from tlie oesopliageal ring anteriorly to tlie 

 bind gut posteriorly. presents the same glandulär structure. Indeed, 

 in Koenenia these simple diverticula in the abdomen seem nierely to 

 have been produced by the flattening of the mid-gut dorso-ventrally 

 through the great development of the reproductive organs; and in 

 the process of spreading, the intestine was constricted laterally at 

 regulär intervals by the dorso-ventral muscles. A most primitive 

 condition is thus found in the digestive tract of Koenenia which, as 

 we should expect, presents a still simpler condition in the younger 

 stages, where the reproductive organs are not developed. It is such 

 a simple arrangement for digestion that I was not at all surprised 

 when I beheld food particles driven from the thoracic diverticula 

 through the straight course of the intestine, into first one and then 

 another of the abdominal diverticula. Dr. Wheeler and myself 

 have Seen this course taken by the food through the intestine in 

 specimens that were brought immediately from the field into the 

 laboratory. The condition of the intestine in Koenenia corrol)()rates 

 Bernakd's Statements concerning (rrt/cofZes, p. 359^): "'The distinction 

 offen drawn between the mit-gut diverticula in the cephalothorax 

 and the "liver" diverticula in the abdomen is erroneous. As I have 

 shown elsewhere the epithelium of these diverticula throughout the 

 whole mid-gut is essentially similar and is throughout digestive in 

 its fuuction. The differences which appear in the epithelia of the 

 cephalothoracic portions of the mid-gut and of the abdominal are 

 not differences of kind : they are due to the fact that the latter have 

 more food pumped into them to digest. The diverticula throughout 

 the Arachnida are typically mere extensions of the digestive surface, 

 and are nowhere converted into hepatic or pancreatic glands". Thus 

 Dr. Hansen's concluding sentence, expressing the opposite of Bernakd's 

 view, "We think that the diverticula in question never contain food 

 particles in any order of Arachnida" is proved to be untrue at least 

 for the Orders to which Koenenia and Galeodes belong. 



Any of the above criticisms of Dr. Hansen might have been 

 entirely ignored. since honest results will always speak for themselves 



1) H. M. Bernard, Comparative morphology of the Galeodidae, 

 in: Trans. Linn. Soc. London, V. 6, part 4, 1896. ♦ 



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