298 



ZOOLOGY. 



oe 



Fig. 237. Intestine and testis (t) of a copepod 

 (Pleuroma), side view. , oesophagus ; t>, stomach ; 

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

 tine; c, heart ; vd, coiled vas deferens. After Claus, 

 from Gegenbaur. 



In Lerneonema radiata Steenstrup and Lutken (Fig. 239), 

 we find the lowest term in the series of degradational forms 



of this order. The 

 mouth-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. 

 241) the body is cord- 

 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 

 gnarled roots, while the 

 shapeless sac-like body 

 is filled with eggs. 



In Adheres, we as- 

 cend a step higher in 

 the perfection of or- 

 gans ; the creature is 

 attached by a pair of 



vT-4-^ 4- Fig> 238 - Oanthocamptus caver- Fig. 239.- 

 jaWS WnlCn Unite 10 narum of Mammoth Cave, much Fish -louse of 



form a sucker, the an- enlarged - MRSSt 



tennaa are present, though rudimentary, while - AfterVernlL 

 the abdomen is faintly segmented. A. Carpenteri Packard 

 (Fig. 240) lives on the trout in Colorado, 



