86 REPORT OF N'EW JERSEY STATE MUSEUM. 



attached to the inner side of the opercular arch or just above the 

 pseudobranchise. Such a location was apparently a favorite 

 place. Others were taken from the isthmus, sometimes well 

 anterior, and still others were less numerous about the gill fila- 

 ments. 



Type No. 2000, Academy of Natural Sciences of Philadel- 

 phia. Tullytown, Pennsylvania. From gills of Pomolohus 

 cestivalis (Mitchill), May 28th, 1912. H. W. Fowler. Also 

 several paratypes, besides others (No. 2001) with same data, 

 except taken on May 17th, 191 2. 



{Pomolohus, the alewife, the host from which this species was 

 secured.) 



FamUy LERN^ID.E. 

 Plate 20. 



Anterior antennas short, slender, carrying small bristles. 

 Posterior antennae uncinate, generally project beyond front 

 border of cephalothorax. Maxillipeds very small, weak. Mouth 

 suctorial. Thorax not articulated. Feet and other organs be- 

 longing to thoracic segment absent or rudimentar\'. No eyes. 

 Genital segment of female much elongated. Abdomen rudi- 

 mentary. Egg-sacs double. 



In the young the body of sexually mature forms is very simi- 

 lar to those in the following related families. The larvae vary 

 from a cyclops-like form to those having a twisted frontal fila- 

 ment. In the older and fixed parasitic stage the females are long 

 and worm-like, usually without limbs, and for this reason the 

 present group has been allowed as a distinct family from the 

 PenneUidcc by some writers. Some old females also show 

 irregular excresences from the anterior portion, others with 

 elongated appendages from the genital segment or abdomen. 



Key to the genera. 



a. No appendages on neck below those radiating from head. 



b. No vestiges of feet on under surface of body, nor any appendages 

 representing them. LERNE^nicus 



