304 Mr. T. H. Huxley on the Auditory Organs in the Crustacea. 



XXX. — Zoological Notes and Observations made on board H.M.S. 

 Rattlesnake during the 7/ears 1846-50. By Thomas H. Hux- 

 LEYj Assistant Surgeon R.N. 



[With a Plate.] 



I. On the Auditory Organs in the Crustacea. 



Great discrepancy prevails among the various authorities as to 

 the true nature and position of the auditory organs in the Crus- 

 tacea. 



The older authors, Fabricius, Scarpa, Brandt, Treviranus, una- 

 nimously confer the title of auditory organs upon certain sacs 

 filled with lluid which are seated in the basal joint of the second 

 or larger pair of antennae. 



j\I. Milne-Edwards, in his elaborate researches upon the Crus- 

 tacea*, adheres to this determination, and describes a very ela- 

 borate tympanic apparatus in the Brachyurous genus Maia. 



By the majority of the earlier writers no notice is taken of the 

 sac existing in many genera in the bases of the first or smaller pair 

 of antennae. Rosenthal t however describes this structure very 

 carefully in Astacus jluviatilis and Astacus marinus. He con- 

 siders it to be an olfactory organ, while he agrees with previous 

 writers in considering the sac in the outer antennae as the audi- 

 tory organ. 



Dr. Farre, in his admirable paper in the ' Philosophical Trans- 

 actions ' for 1843, gives very good reasons for exactly reversing 

 Rosenthal's denominations, and considering the sac in the first 

 pair of antennae to be the auditory organ, while the sac in the 

 second pair is the olfactory organ. Dr. Farre doubts the exist- 

 ence of true auditory organs in the Bracliyura. 



Siebold in his Report upon the progress of the Anatomy of 

 the Invertebrata for 1843-44 J, mentions Dr. Farre's views, but 

 seems to doubt their correctness ; and they have had no better 

 reception from Prof. Van der Hoeven§ and Erichson||. 



The matter stands thus at present then. It is universally 

 acknowledged that in the Macroura there exists in the basal joint 

 of both the first and second pair of antennae a sac containing a 

 liquid, and that in the Brachyura such a sac exists at least in the 

 second pair. According to the majority of authors the sac in the 

 second pair is the auditory organ ; and according to Rosenthal 

 the sac in the first pair is the olfactory organ. 



On the other hand, if we take Dr. Farre's interpretation, the 



* Hist. Nat. des Crustaces. Suites a Buffon. 



t Ueber die Geruchsorganen d. Insekten. ReU's Archiv, B. x. 1811. 

 X Miiller's Ai-chiv, 1845. § Handbuch d. Zoologie, p. 59?. 



II Erichson's Archiv, 1844. 



