NO. 1805. DE8CRTPTI0WS OF NEW C0PEP0D8— WILSON. 633 



The mandibles are short and stout, each bent near the center and 

 armed at the tip with four large teeth and three small ones. 



The first maxillae are of the usual pattern; the second pair are at 

 the extreme posterior margin of the head, are cylindrical in shape, 

 and nearly as long as the body. The cord extending from the end 

 of these appendages is stout, about half the diameter and one-fifth 

 the length of the "arms" themselves, and terminates in an enormous 

 umbrella-shaped bulla, whose diameter is considerably larger than 

 that of the creature's body. 



From the junction of the stem with the umbrella a series of ridges 

 radiate outward toward the edge of the bulla, very similar to the 

 ribs of an umbrella. The maxillipeds are situated a short distance 

 in front of the second maxillae, are stout, three-jointed, and entirely 

 destitute of claws or armature of any sort. 



The egg cases are cylindrical, as long as the thorax and nearly 

 half as wide, and are carried turned forward against the sides of the 

 thorax. The eggs are rather small and are arranged in twelve to 

 fifteen longitudinal rows, about twenty-five eggs in a row. 



Color, a uniform light orange yellow. 



Total length 4.6 mm. Length of head 2 mm., of thorax 2.6 mm., 

 of second maxillae 3 mm., of egg-strings 2.6 mm. Diameter of egg 

 strings 0.8 mm., of bulla 2.2 mm., of thorax 1.8 mm. 



Three lots of this species, each consisting of a single specimen, 

 were taken from the upper angle of the gill cavity of Leucichthys Jia- 

 rengus, at the follov/ing localities: Blind River, Lake Huron; Bay 

 Port, ]\Iichigan; Marquette, Lake Superior. One hundred and forty 

 specimens were obtained from the same host taken in trap nets at 

 Saginaw Bay, Lake Huron. 



All of the specimens were collected by the U. S. Bureau of Fish- 

 eries through Dr. B. W. Evermann. 



Type-locality. — Knife River, Duluth, Minnesota. 



Type-specimen.— Cat. No. 42283, U.S.N.M. 



The species is closely related to L. extumescens Gadd, but differs in 

 the arrangement of the appendages, and especially in the shape of 

 the mandibles and the teeth with which they are armed. The com- 

 parative size of the bulla is also a prominent character and perhaps 

 the easiest one to recognize. 



