14 MICHIGAN FISH COMMISSION— BULLETIN NO. 5. 



/ 

 SECOND AND THIED FEET. 



Outer br. ex. 3 spines. Inner br. ex. 1 seta. 



ap. 1 spine, 1 seta. ap. 1 spine, 1 seta. 



in. 4 setae, in. 3 setae. 



FOURTH FEET. 



Outer br. ex. 2 spines. Inner br. ex. 1 seta. 



ap. 1 spine, 1 seta. ap. 2 spines, 



in. 4 setae, in. 2 setae. 



The fifth foot is one-jointed, and armed with a stout spine and two long 

 setae. 



Average length 1. 77 mm. 



A large, very robust form, of striking appearance because of its deep 

 colors. The colors of the St. Clair specimens were as follows: antennae, 

 antennules, swimming feet and furcal setae dark blue, almost black. The 

 caudal margins of the cephalothorax have the same color. On each side 

 of the abdomen, and extending to the ends of the furcae is a strip of the 

 same color but darker. Borders of the cephalothorax tinged with green. 

 Oviducts white. The ovary is orange. 



To the naked eye it resembles closely in form, size, and color an Arre- 

 nurus with which it is found associated. This may be a case of protective 

 mimicry. 



This species was originally described by Herrick in 1882, and is men- 

 tioned by him in his succeeding reports of 1884 and 1887, but has been 

 noted by no other author. It was discovered by Professor Reighard in 

 the St. Clair collections, and was worked out very thoroughly by him. It 

 is from his notes that the above description is taken. 



This seems to be a somewhat rare form in this region. I have found a 

 few individuals in Rush Lake, Wisconsin, and in Michigan, besides in the 

 St. Clair collections, have found it in Twenty-Sixth Lake, Intermediate 

 Lake and Susan Lake. Where it occurs it is easily detected because of its 

 large size and prominent colors. The specimens from Round Lake had 

 more of the red color, so much so that this, on a superficial examination, 

 seemed to be the most prominent color. 



Cyclops brevispinosus Herrick. 

 Plate VII, fig. 12. 



1884. C. brevispinosus Herrick, p. 148, pi. S, figs. 7-11. 

 1893. " " Marsh, p. 205, pi. IV, figs. 11 and 12. 



C. brevispinosus occurred in the collections from Lake St. Clair, the 

 Detroit river, Lake Erie, Susan Lake, Beaver Island, Intermediate Lake and 

 Round Lake. I have found it in collections from Lake Superior and Lake 

 Ontario, but, curiously, never in Lake Michigan collections. 



