278 



ZOOLOGY. 



In Lerneonema radiata Steenstrup and Lutken (Fig 234), 

 we find the lowest term in the series of degradational forms 



of this order. The 

 rnouth-parts are here 

 converted into five 

 roots, radiating from 

 the head ; the body 

 is not segmented, and 

 ends in two long egg- 

 masses. 



In Penella (Fig. 

 236) the body is cord- 



oe 



Fie. 232. Intestine and testis (0 of a copepod 

 (Plewoma), side view OB, oesophagus ; v, stomach ; 

 A, blind sac leading from the stomach ; i, intes- 

 tine; <-, heart ; vd, coiled vas deferens. After Clans, 

 from Gegenbaur. 



like, buried in the 

 flesh of the sun-fish or sword-fish, etc., the females having 

 two long, string-like 

 egg-sacs. The speci- 

 men figured was taken 

 from a sword-fish off 

 Portland, Maine. 



In Lerncea branchia- 

 lis Linn, of the gills of 

 the cod, the body is 

 thicker, the root-like 

 appendages grow deep 

 into the flesh of its 

 host, like twisted and 

 gnark'd roots, while the 

 shapeless sac-like body 

 is filled with eggs. 



In Aether eft, we as- 

 cend a step higher in 

 the perfection of or- 

 gans ; the creature is 



attached bv a pair of 



Fig. 233. Canthocamptus caver- Fig. 234- 

 tO narttm of Mammoth Cave, much Fi^h - louse ot 



form a sucker, the an- 3i3SS& 



tennae are present, though rudimentary, while - AfterVerrilL 

 the abdomen is faintly segmented. A. Carpenteri Packard 

 (Fig. 235) lives on the trout in Colorado. 



