ART. XL-DESCRIPTIONS OF NEW PHYLLOPOD CRUSTACEA 



FROM THE WEST. 



By a. S. Packard, Jr., M. D. 



Fias. 11-14. 



The species described in the following paper were discovered by Dr. 

 L. Watson, at Ellis, Kans., in 1874, and by Dr. Elliott Cones, United 

 States Army, naturalist to the United States E"orthern Boundary Survey. 

 The collections of Dr. Watson from Kansas were of much interest, as 

 containing a remarkable new form of the group BrancMpodidce^ quite un- 

 like any other known genus ; an interesting iStre2)toce2)Mlus, forming the 

 second species known to inhabit North America ; a new Limnadia and 

 Lymnetis, while the occurrence of A2)us lucasanus, in great numbers, 

 shows that the range of this species is wide, and that over that range 

 it is exposed to little or no variation. Regarding the collections he 

 made, and which are here identified and described. Dr. Watson writes 

 me as follows, dated Ellis, Kans., July 8 : — " 1 have to-day sent you, by 

 express, a small box, containing the Crustacea mentioned in my letter 

 of June 26, and such as I could collect from various pools up to July 4. 

 The pool from which I pulled the weeds, and from which I got what I 

 sent by mail, was all dried up upon my visit to it a few days afterward. 

 I worked diligently up to July 4, when I got the last. I have ceased 

 to look farther, for the pools, where they are likely to have been, are all 

 dried up." On November 12, he writes : — "The first slight frost we had 

 was on the morning of October 12; the next slight one on the 16th ;, 

 none again till the 29th. On the 31st, the temperature was 18° in the 

 morning, and 24°, 26°, 28°, November 1-3. After that, no frost till No- 

 vember 8. On November 6, 1 got a few Estheria [clarMi] from a pool 

 in which I had seen Apus [lucasanus] ; but the latter had disappeared 

 at that date. All but the smaller Branchipus-Vike form [Streptocephalus 

 watsonii] have not been abundant this fall. I have had to watch for 

 single ones, and could capture only one at a time, except, occasionally, 

 two Estheria would be united, possibly in copulation." In July, when 

 collecting the others, the thermometer stood at 10S°-110° in the shade. 

 On December 21, 1874, he again wrote me as follows : — " I drop you a 

 postal card to say, that from some dried mud of an extinct pool, to 

 which, in a goblet, I added water, there are now hatched out some of the 

 Branchipus-like forms [Streptocephalus watsonii] ; also Estheria [clarMi] 

 and some insects. The former have grown to the length of two-tenths 

 of an inch within a few days from mere specks, only noticeable by their 



171 



