ENTOMOSTKACA OF MINNESOTA. 125 



First — As a matter of frequent observation and beyond all doubt, 

 it frequently happens that a young female Cyclops becomes oviparous 

 before the moult, when it acquires its full adult complement of seg- 

 ments in the antennie and feet. Such animals are obviously larval and 

 exhibit this fact in their small size, pale color, small number of eggsr 

 imperfect development of serrations, spines, etc. Schmeil himself 

 has observed males in this stage with spermatophores and had before 

 him a figure in my Final Report (Plate Q, 5), reprinted from the tenth 

 annual report, in which this matter is plainly stated, of young gravid 

 females of G. serrulatus — a species not likely to be mistaken — with 

 less than twelve joints in the antennae and two-jointed rami of the 

 swimming feet. After admitting that "kein Grund vorliegt, an der 

 Richtigkeit der Herrick'schen Angabe zu zweifeln," he says "Herrick 

 figures, as a matter of fact, not a young form but a completely devel- 

 oped animal, in which, to be sure, in certain segments of the antenna 

 the normal subdivision has not taken place." He adds (entirely mis- 

 conceiving my position as to heterogeny' : "Dass hier nicht an einem 

 Fall von Padogonie oder gar Heterogenic zu denken ist, ist selbstvers- 

 tandlich." Had he consulted the original paper Schmeil would have 

 seen that the failure to develop a full complement of antennal joints is 

 but one of the symptoms of the larval state manifested by this speci- 

 men. Moreover, such forms are found among vast numbers of adults 

 and larvaj in the midst of the most prolific seasons and in suitable 

 situations. We claim that the next moult would have brought to this 

 very animal its normal adult structure. Nor is this an isolated case. 

 Yet Schmeil could in all consistency be forced to erect a variety for 

 such forms. In glaring inconsequence, we find, on p. 101, Schmeil 

 says of G. clausii Heller: "Obgleich ich der Ansicht bin, dass wir es 

 hier wohl kaum mit einer selbstiindigen Art, sondern nur mit einer 

 Jugendform einer anderen (des G. viridis) zu thun haben," etc. 



Second — As a second and entirely distinct point, though confused 

 with the former by Schmeil, it is believed that many of our species, 

 especially such as live in pools which undergo great changes with the 

 season by reason of evaporation, intrusion of water plants or animal 

 forms serving as food, etc., may, after reaching full maturity and bear- 

 ing more than one generation of eggs, undergo considerable changes, 

 or that, under these changed conditions, what is usually the ultimate 

 condition becomes a transitory one. This change may show itself not 

 only in increased size but in enormous enlargement of the setje. For 

 example, I have seen G. ingens with the pectinating hairs on the sette 

 elongated till they became long hairs. All the spines and plates and 

 serrations are exaggerated, while the relative proportions are altered. 



In the case of G. viridis this is especially liable to occur, because of 

 its stagnant stations. The color changes with the rest and the change 



