134 



EPIZOA. 



tive anatomy. In the CRUSTACEA, the organs of circulation and 

 respiration are well developed and easily recognisable ; but, in the 

 class we are now considering, no parts adapted to either of those 

 functions have hitherto been satisfactorily discovered : neverthe- 

 less, that the EPIZOA form a gradual transition from the humbler 

 creatures we have hitherto examined to the great division of ar- 

 ticulated animals, must be obvious to the most superficial observer. 



(177.) In Lamproglena pulchella we have a still more decided 

 approximation to the crustacean type of structure, and the rudimen- 

 tary feet arranged in symmetrical pairs are as numerous as the 

 segments of the body. The limbs, however, are as yet only 

 adapted to secure a firm hold upon the structures to which this 

 parasite attaches itself, namely, the gills of the chub (Cyprinus 

 Jeses), in which situation it is most usually found. The two an- 

 terior pairs (fig. 56, b, c) are far more large- Fig. 56. 

 ly developed than those which are placed 

 upon the posterior parts of the animal, and 

 are apparently strengthened by a cruciform 

 cartilaginous frame-work seen through the 

 transparent integument. The first pair of 

 these holding feet consists of two robust 

 and powerful hooks, terminated by simple 

 horny points ; whilst the second, which are 

 likewise unciform, terminate in trifid prongs, 

 and are evidently equally adapted to pre- 

 hension. The four pairs of members which 

 succeed to these are mere rudiments, and 

 can be of little service as organs of attach- 

 ment ; but, to make up for their imperfec- 

 tion, we find at the posterior^ extremity of 

 the body, between the orifices of the ovaria 

 (g), a pair of cartilaginous suckers well cal- 

 culated to fix this part of the animal. 



The muscular system is readily seen 

 through the transparent skin : four longitudinal bands are visible 

 (d), running from one end to the other, and, besides these, broad 

 transverse fasciculi are discernible in the fifth and sixth segments of 

 the body ; from the nature of the feet, however, and general struc- 

 ture of the creature, we must imagine the existence of muscles 

 provided for the movements of each articulated member, although, 

 from their extreme minuteness, they escape detection. 



