64 Prof. C. Glaus on ihe 



Arachnida and the anterior limbs of Limulus as equivalent to 

 the anterior antennae of the Crustacea, I characterize the 

 Arachnoidea and Gigantostraca by the absence of the anterior 

 antennas, whicli I correlate with the antennae of Insects, 

 Myriapods, and Periimtus. Formerly indeed, in my work 

 upon the Crustacean system, I correlated the anterior members 

 of Limulus^ like the falces of the Arachnoidea, with the ante- 

 rior antennge of the Crustacea ; but this interpretation was 

 founded upon the erroneous notion, supported by the state- 

 ments of authors, that the nerve belonging to them originates 

 from the cerebrum. But since I became acquainted with the 

 demonstration given by Alphonse Milne-Edwards, that this 

 nerve, in opposition to the statements of Van der Hoeven, 

 Owen, and Huxley, really originates from the oesophageal 

 ring, I regard the interpretation of the anterior pair of mem- 

 bers as belonging to the trunk as incontestable, while, on the 

 other hand, I can see no obstacle to the homologization of the 

 falces with the anterior limbs of Limulus, in the circumstance 

 that the nerves passing to the falces of the Scorpions originate 

 from the cerebrum, considering the other reasons in favour of 

 the morphological relationship of the Gigantostraca and 

 Arachnoidea. Just in the same way that the nerve of the 

 second antenna of the Crustacea, originating from the oeso- 

 phageal ring, becomes a cerebral nerve in the higher types of 

 that class, a similar condition may also be developed in the 

 second Arthropod series, and the nerve originating from the 

 cerebrum in the higher type of the Arachnoidea may have 

 belonged, in the Gigantostraca, as still in Limulus, to the 

 oesophageal ring, and consequently to a trunk-ganglion ; in 

 other words, the nerve of the falces of the Arachnoidea has 

 only secondarily become a cerebral nerve. From tliis mode 

 of argumentation, which is quite different from Ray Lan- 

 kester's, I have characterized the second Arthropod series by 

 the reduction of the prgeoral region of the head and the 

 deficiency of the first pair of antenncBj without the least refer- 

 ence to any opinions of Prof. E,ay Lankester, with which 

 mine have nothing in common. How complete this contra- 

 diction is, especially in the province of the Crustacea, Ray 

 Lankester may ascertain from my investigations of recent 

 date, which, indeed, appear to be equally unknown to him with 

 the earlier ones. If Ray Lankester had only a remote presen- 

 timent of this contradiction, which is founded on the whole 

 method of putting forward the question, on the mode of 

 investigation and drawing conclusions, he would certainly 

 have kept himself free from the apprehension that on the 

 next favourable opportunity I might perhaps appropriate 



