2 Prof. J. C. Schiodte on the Structure of 



tion of the organs of the mouth in masticating Condylopoda, 

 founded on careful consideration of their anatomic connexion 

 with one another, and, on the other hand, a definition of the 

 morphological equivalents of all the different parts which 

 shall prove its own correctness by its self-consistency. With 

 less preparation than this it would he useless to attempt an 

 interpretation of the structure of the mouth in sucking Condy- 

 lojooda. 



It is one of the imperishable merits of Savigny that he has 

 solved this problem in all essential points with regard to 

 Insects ; but with regard to Crustacea almost everything still 

 remains to be done. In this class the investigation becomes 

 complicated by the circumstance that the body is more or less 

 united with the head, so that a varying number of its foremost 

 pairs of limbs may be assimilated to the organs of the 

 mouth in point of form and use. It will therefore be advan- 

 tageous to begin our investigation with the order of Isopoda. 

 On the one hand, this order occupies one of the highest steps 

 to which the class of Crustacea upon the whole attains in the 

 scale of development of the articulate type, whereby the com- 

 parison with the mouth of insects is much facilitated ; whilst, 

 on the other hand, it descends so low as to contain numerous 

 parasitic species, and, therefore, is more likely than any other 

 order to supply the key for the interpretation of the mouth in 

 sucking Copepoda. How far this latter expectation will prove 

 true cannot be shown more explicitly in this first paper; 

 but the initiated will no doubt at once discern the application 

 of the present analysis to lower forms. 



2. Although it is sufficiently well known that at least some 

 Cymothoge live upon liquid food, and although Rondelet, more 

 than three centmies ago, has said, concerning one of these para- 

 sites, that it sucks like a leech*, the question of the structure of 

 their sucking-apparatus is nevertheless, in a scientific point of 

 view, entirely virgin soil. It is true that Bosc believed that 

 he observed in a CymotJwa a retractile sucker with a pair of 

 small palpi t ; but Latreille declares that he could not find any 

 such organ, and that he should consider it an anomaly in that 



* " Piscibus ita haeret, ut eripi non possit, sugit ut hirudo, nee prius 

 abscedit, quam tabidum et exsuccum piscem reddiderit, reperitur cervici 

 mug-ilum, liiporum, et saxatiliimi piscium affixus." (Libr. de Pise. mar. 

 Lugd. 1554, p. 576, " De Pedieulo marino.") The woodcut at the head 

 of Rondelet's article on Pediculus marinus represents an Anilocra, and 

 approaches nearest to A. mecliterranea, Leach. 



T Hist. Nat. des Crust, in Deterville's small edition of BufFon, ii. 

 p. 208. The figure shows that the species on which Bosc has founded his 

 description of the genus was a Cymothoa sens, strict.; Brunnieh's " Fiske- 

 bjorn" (Entom. fig. 5), which he quotes, was more probably an Anilocra. 



