STATE GEOLOGIST. 131 



prehensile appendage on the left side, often more or less distorted. 

 Inner rami of swimming feet one-jointed. Caudal stylets with 

 three long setae. The first mention of an animal of this genus 

 seems to be Pickering's description of Scopiphora vagans from deep 

 water in lake Ontario. It seems almost certain that the species so 

 imperfectly described in Dekay's Crustacea of New York, is none 

 other than a species of Epischura, but [ hesitate to substitute for 

 a name accompanied by good descriptions and figures, and one 

 which has already been incorporated, to some extent, into our 

 literature, one which is founded on a description so imperfect and 

 general that one incidental character alone enables one to guess its 

 application. The following is Pickering's description: 



'^ Body small, eye single, near the anterior margin of the shield. 

 Antennse large, and as long as in the preceding genus [Cyclops], 

 and has the same motions in the water. Abdomen termmatiuor 

 in two styles, each with three setae; last or three last joints. Ova- 

 ries none; legs spiny." 



What is meant by the "brush" fails to appear, unless the speci- 

 mens were ornamented with some parasitic plants or animals. 

 The three setas of the caudal stylets and long antennas will place 

 this form in no American genus save Epischura. But even this 

 statement of Pickering may be held doubtful. 



Sp. 1. Epischiu'a lacustris, Forbes. 

 I 



( Plate Q. Fig. 15.) 



" The scond segment of the abdomen of the male is twice as long 

 as the first, and produced to the right as a large, elongate, trian- 

 gular process, somewhat hooked backwards at the tip. The third 

 segment is similarly produced, but rounded and expanded at the 

 tip, which is roughened before and behind. 



From the right side of the fourth segment arises a stout process 

 bearing at its apex a hatchet-shaped plate with seven broad obtuse 

 serratures on its anterior margin. This process is roughened be- 

 hind, where it is opposed to the concave side of the left ramus of 

 the furca. From the same side of the fifth segment, a short flat- 

 tened plate, of a spatulate or pad'dle-like form, extends forward 

 above or beyond the toothed process just mentioned. 



The antennae are 25-jointed, and reach to the second segment of 

 the abdomen. There are especially prominent sensory hairs on the 



