STATE GEOLOGIST. 121 



ADDENDA. 



Since these pages were written the Bulletins of the Illinois Museum of Nat . 

 Hist, have come under my notice, which, aside from other interesting matter, 

 contain descriptions of many new species of Crustacea inhabiting the water of 

 that state. Fine descriptions are given of the followmg species of Entomostraca, 

 to which the student is referred, viz : 



Eubranchipus serratus, Forbes. 



Canthocamptus Illinoisensis, Forbes. 



Diaptomus Sanguineus, Forbes. 



Eubranchipus Bundi/i, Forbes. 



In Bulletin No. 2, Prof. Forbes describes or mentions the following: 



Eurycercus lamillatuSy Mull. ? . 



Bosmina, sp.? 



Ceriodaphnia angulata, Say. 



Daphnia pulex, L. ? 



Daphnia galeata, Sars. 



Later study shows that there is yet much to be done in simply verifying tiie 

 species which occur here, not to mention the ever remaining opportunity for more 

 minute study of the structure of known forms, for aside from the whole genus 

 Cijdops, which has not yet been attempted, and contains numerous species, new 

 species are constantly being met with, among which are those described beyond . 



FAMILY PENILID^. 



Genus Daphnella. Baird. 



Bibliography. — Daphnella, Baird, Bnt. Entomost., 809. 



Dana, Wilkes' Exp. Crust., page 1267. 



Another member of this interesting family has been found since the text was 

 sent to press. 



The genus Daphnella is characterized by Dana as follows: Posterior antennae 

 with both rami two-jointed, the shorter ramus often imperfectly three-jointed : 

 Head oblong, not prodiiced beneath, bearing the anterior antennas near the 

 middle. Daphnella differs from Sida, which it greatly resembles, even in 



