382 Wisconsin Academy of Sciences, Arts and Letters. 



NOTES ON THE PEECEDING LIST. 



Species 1. Holopedium gibbeeum, Zad. 



I have found this species only once in Madison. It is quite abundant 

 in collections from northern Minnesota, and Forbes* notes its occurence 

 at Grand Traverse Bay, Lake Michigan. 



Species 2. Sida ceystallina, O. F. Muller. 

 No specimens were found belonging to the form 8. elongata, DeGeer. 



Species 3 and 4. Daphnella beaohyuea, Liev. and D. beandtiana Fisch. 

 Of those closely allied forms I have only to say that both are found 

 with us, and show exactly the same differences as described and figured 

 by Sars in his Norges FersJcvandskrebsdyr. D. brachyura is usually found in 

 open water, and D. brandtiana in marshes. I cannot state this as a law, 

 however, as both forms are found together sometimes, in either kind of 

 locality. 



Species 5. Latona setifeea, O. F. Muller. Plate XIII. Fig. 6. 



Our specimens of Latona have one peculiarity not mentioned by any 

 European writer. There is a thick coat of short hairs on the head, body 

 and antennae. These hairs are .02 mm. or less in length, are close set and 

 give the outline a velvety appearance when seen by transmitted light. 

 P. E. Muller | says: " Hvad der er aldeles eiendommeligt for Latona og 

 neppe jagttaget hos nogen anden Cladoceer, eret fint Lod af ganske korte 

 Haar, der isaer findes over Matrix; det er vanskeligt at see og opdages 

 kun ved staerkt Sidelys." This exact account shows that his specimens 

 were not villous as ours are. The hairs are conspicuous in any light and 

 are very easily seen. No other European writer mentions a similar struc- 

 ture. A more extended study of specimens from different localities will 

 show whether this is a local peculiarity or is characteristic of a distinct 

 variety. On old females which have not moulted recently the hairs are 

 worn off. 



The male antenna differs somewhat from the account given by Sars.J 



The appendix ciliata is much larger than Sars figures it, and is situ- 

 ated at the same level as the sense-hairs instead of distal to them. 

 The size, number and arrangement of the setae on the edge of the cara- 

 pace differ from the details given by Sars, but not in any very important 

 respect. 



Latona seems to be rare in Europe, but the apparent rarity is, as Sars 

 says, probably due to its mode of life and the method of collecting. In 

 late summer and early fall, one can be certain of obtaining a good num- 



* Forbes, S. A. On some Entomostraca of Lake Michigan and adjacent Waters. Am. 

 Naturalist, vol. xvi., p. 641. Aug., 1882. 

 t Muller, JP. E. = Danmarks Cladocera, pp. 97-98. : 

 t Norges.Ferskvandskrebsdyr, p. 55, PI. Ill, figs. 17a, 17b. 



