DESCRIPTIONS OF AUG ULID.E— WILSON. <*) 5 1 



Just in front of the opening, upon the anterior part of the ventral 

 surface, are two rounded papilliB, covered with rough tubercles. This 

 receptacle is tilled with semen from the testes, probablv through the 

 agency of the peg. though this was not actually observed. Once fiUed, 

 however, it operates as follows: The sphincter muscle around the open- 

 ing relaxes enough to allow the entrance of the peg on the fourth leg. 

 Being protruded as far as possible and the sides of the basal pai)illa 

 being compressed b}" internal muscles, the peg tube acts like a pipette 

 and becomes tilled with semen from the receptacle. It is then with- 

 drawn and inserted in the opening of the duct leading to the semen 

 receptacle in the abdomen of the female. The sides of the basal papilla 

 are again compressed, the internal muscles being aided by the rough 

 papilhv on the ventral surface of the fourth leg, which bend over and 

 seize the base of the peg securely, one on either side. By this means 

 the peg is emptied of its contents again ver}^ similarly to a pipette. 



ARGULUS TRILINEATA, new species. 



The U. 8. Fish Commission recently received from Messrs. King 

 and Oliphant, pharmacists, of Macon, Georgia, a single specimen of a 

 female Argulus taken from one of their goldfish. This was forwarded 

 to the author for identification, and proves to be a new species, with 

 characters as follows: 



Carapace elliptical, reaching well beyond the base of the abdomen, 

 with the longitudinal and transverse diameters in the i)roportion of 

 14:12.5 (fig. 34). The posterior sinus is three-sevenths the length of 

 the carapace and a little more than twice as long as wide. The antero- 

 lateral sinuses are so shallow as to l)e scarcely perceptible, so that the 

 cephalic area does not project appreciably. The central longitudinal 

 ribs are close together and nearly parallel; the joints in them behind 

 the brain are indistinct and easily overlooked. The horseshoe suture 

 is long and narrow and comparatively pointed at the posterior end, 

 leaving the lateral areas very symmetrical and about the same size 

 anteriorly and posteriorly. The thoracic area of the carapace, behind 

 this suture, is a short strip one-fourth as long as wid(> and only half 

 the length of the first free thoracic segment. 



These thoracic segments increase in lejigth from in front backward, 

 the posterior one being more than twice as long as the anterior. They 

 also increase somewhat in breadth, and since the posterior sinus of the 

 carapace is about the same width, the free thorax is almost eiitiivly 

 exposed. 



The abdomen is very small and spindle shaped, one-quarter the 

 length of the rest of the l)ody and two-thirds as wide at the center as 

 it is long. The anal sinus is cut just to the center, and is narrow but 

 of uniform width, leaving stout, bluntly conical lot)es: the anal inipilliv 

 are small and ])asal. 



