728 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv. 



ARGULUS SCUTIFORMIS Thiele 



Argulus seutiformlx Thiele, 1901. 



The male has an oval shield which covers half the abdomen ; antero- 

 lateral sinuses ver}^ deep. Anal sinus of abdomen very short, leaving- 

 short rounded lobes. Spines on the first antennae reenforced. Poste- 

 rior maxillipeds short and stout, with short sharp teeth; basal plate very 

 large and covered with papillar}^ warts. Swimming legs completely 

 covered by the carapace; flagella on the second legs rudimentary. 



No copulatory organs except the regular peg and semen receptacle. 

 Color brownish; no figure published. 



Length 12 mm. ; width 8 mm. Female unknown. 



Habitat. — The single specimen is in the Vienna Museum and came 

 from Japan. Host unknown. 



{sGut^ln^— shield, forma=!iihsiY>Q.) 



ARGULUS PHOXINI Leydig. 



Plate XXVII, fig. 91. 

 Argulus phoxini Leydig, 1871. 



Carapace orbicular, about as wide as long; anterolateral sinuses 

 shallow. Grooves between the cephalic area and the lateral lobes 

 well defined, separating the two sharply; lobes curved inward toward 

 each other till they almost meet posteriorly. Ribs supporting the 

 carapace well defined, the longitudinal ones forked at the anterior end 

 as in foliaceus; abdomen elliptical, more than three-fifths the length 

 of the rest of the body; anal sinus cut beyond the center; lobes acute 

 and flaring at the tips; papilhie lateral, about one-fourth the distance 

 from the base of the sinus. 



Sucking disks small, less than 0.16, widely separated; rays composed 

 of elliptical rods placed end to end. Posterior maxillipeds rather small 

 but well armed; basal plate elliptical, thickly covered with spines. 



Swimming legs reaching l)e3^ond the edge of the carapace; lobes on 

 the posterior pair small and orbicular with no trace of a boot-shape. 

 In the male the testes are very large, filling the entire l)asal portion 

 of the abdomen. The peg is covered with long finger-like protul)er- 

 ances or papillae, while the receptacle takes on a peculiar warty or 

 knobbed appearance, due to numerous small protuberances scattered 

 over its surface. 



In addition to these there is on the anterior margin of the basipods 

 of the third legs a pair of accessory organs consisting of a curved hook 

 at the base of the terminal joint and a short papilla thickly covered 

 with spines oppo.site the hook at the distal end of the second joint. On 

 the posterior margin of the basal joint of the second legs is a knobl)ed 

 protuberance somewhat similar to the receptacle in appearance. 



