Internal Anatomy of TJropoda Krameri. By A. D. Michael. 3 



seemed to me a favourable opportunity for ascertaining something 

 about the internal anatomy. As I investigated the matter I found it 

 very interesting ; especially from the numerous resemblances to the 

 corresponding organs in the Oribatidse, which I had previously 

 studied. The main features of the internal structure turned out, as 

 might be expected, to be essentially of the Gamasid type, still there 

 were found to be many points in which there was an approach to the 

 organization of the Oribatidse ; thus showing that the external resem- 

 blance which deceived Hermann was accompanied by certain modifica- 

 tions of the internal parts, producing a condition somewhat inter- 

 mediate between the types of the two families. 



The investigations were carried on entirely by dissection, in the 

 same manner as I had previously conducted those relative to the 

 Oribatidse* Preparations of the actual organs therefore remain in 

 my possession for reference, and as proofs of the correctness of these 

 notes. All dissections have been frequently repeated. 



Upon my return to London, I found that during my absence an 

 important and excellent paper upon the anatomy of the Gamasidm 

 had been published by Herr Willibald Winkler.j This paper, although 

 it principally treats of the anatomy of the genus Gamasus, deals also 

 to a lesser extent with that of Uropoda obseura (Koch). Herr Winkler's 

 investigations were clearly prior in date to mine, but of course mine 

 were conducted, and this paper written, and the drawings made in 

 entire ignorance of them. Under these circumstances our observations 

 necessarily cover a portion of the same ground ; but on the other 

 hand, large parts of the two works do not overlap. Herr Winkler's 

 treatise is greatly devoted to the histology of the subject and to the 

 mouth-parts, the nerves, &c., which I have not touched upon ; while 

 I think a good deal will be found in the following pages that has not 

 been included in Herr Winkler's investigations, and, indeed, many of 

 the organs may differ, or may not exist, in the species which he has 

 selected. I thought at first that it would be better to eliminate from 

 this paper snch portions as were covered by the German memoir, but 

 I found that doing so would render the remainder obscure, the con- 

 nection of subjects being broken. I have therefore thought it best to 

 retain them, making this acknowledgment of Herr Winkler's 

 priority, but I have usually mentioned where he has described the 

 same thing, and of course I have pointed out any differences which 

 have struck me, although these are not numerous nor specially 

 important. 



General Arrangement of the Organs. Fig. 7. 



When the dorsal shield, and the fatty matter which underlies it 

 are removed from Uropoda Krameri, and the muscles of the mandibles, 

 &c., so far cut away as to enable the operator to see the other parts 

 clearly, the arrangement of the principal organs is found to be that 



* ' British Oribatidse,' Eay Soc, 1884, p. 142. 



t " Anatoraie der Gamasiden," Arbeit. Zool. Inst. Univ. Wien, vii. (1888) pp. 317-45. 



B 2 



