NO. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILHON. 23 



narrower than the genital segment, and is often reduced to a mere 

 knob. To this abdomen are attached various kinds of appendages 

 in some of the genera. In Fennella and PegesiTnallus tliere are very 

 long rows of branched barbules, from which the former and better 

 known genus derives its name. In Lernaeolophus there are similar 

 appendages massed together closely, so that they bear more resem- 

 blance to a yarn mop than to the barbules of a feather. In Uaemo- 

 baphcs and Hiiemohaphoides there are two or three large knobs or 

 processes along either side. In the other genera the abdomen is with- 

 out appendages. 



The egg strings vary greatly in the different genera, not only 

 in their general makeup, hut also in the arrangement of the eggs in- 

 side the string. In the Lernaeinae the cases are sacklike and the 

 eggs are multiseriate ; in all the other genera the cases are thread- 

 like and the eggs are uniseriate. The multiseriate egg strings are 

 shorter than the body and straight, while the uniseriate egg strings 

 are often many times the length of the body, and are either cylin- 

 drical and straight, or coiled into a loose snarl, or flattened laterally 

 and curled into a tight spiral. 



Th£ appeTidages. — Tliese are the same as those of the Lernaeopo- 

 didae, namely, two pairs of antennae, a pair of mandibles, two pairs 

 of maxillae, a pair of maxillipeds, and four or five pairs of swim- 

 ming legs. These are all present in the sexually ripe male, but some 

 of them are usually wanting in tlie female. 



The first or anterior antennae are simple jointed cylinders, well 

 armed with short setae, and are evidently tactile sense organs. The 

 second or posterior antennae are also simple jointed cylinders, short, 

 stout, and strongly chelate. They serve as the principal organs of 

 prehension during the larval stages and often maintain that func- 

 tion in the matured female (Feniculus, etc.). 



The proboscis is made up of a fusion of the upper and under 

 lips, often combined with a considerable portion of the ventral sur- 

 face of the head. 



In this latter form it is Aery extensile and may be protruded a 

 considerable distance from the head and moved about freely, the 

 movements being controlled by numerous powerful muscles. When 

 strongly retracted, as sometimes happens during preservation, it is 

 drawn in so far as to produce a saucer-shaped or bowl-shaped 

 depression of the ventral surface of the head. Wlien protracted 

 the maxillae are carried along with it and are then found near the 

 tip of the proboscis, a considerable distance from the ventral surface 

 of the head. In those genera (Lernaeolophvs) where the ventral 

 surface of the head is chitinized and takes no part in the movements 

 of the mouth tube, the latter is always withdrawn in prpsorvation 



