AKT. 1 



A NEW PRESH-WATEB COPEPOD WIL.LEY 



3 



tical and nearly one-half the length of the ovisac. The abdominal 

 segments or segments of the iirosome are five in number (Abl to 

 Ah5) . In the female, Ahl and Ah2 have coalesced to form the com- 

 posite genital segment; in the male they are separate. With this 

 reservation, the same symbols can be employed for both sexes. The 

 segments are smooth dorsally but carry rows of spinules laterally and 

 ventrally near the hinder borders. The distribution of the ventral 

 spinules offers specific characters. 



FiOS. 1-2.— MORARU LADRENTICA. 1, FkMALE INSIDE VIEW. 2, THE LAST TRUNK SEGMENT AND GENI- 

 TAL SEGMENT .SHOWING THE FIFTH FOOT AND THE OVISAC 



In M. schmeili the ventral and lateral spinules form together a 

 single row on Ah4; on AhS the ventral spinules are separated from 

 the lateral by an interval on each side. In M. laurentica the ventro- 

 lateral rows of spinules are complete on Ab4 and on AhS in both 

 sexes. On Ah2 there are no ventral spinules in the female, the lat- 

 eral groups being separated by a wide gap (fig. 3) ; but in the male 

 there is a complete row of spinules on this segment in M. schmeili, 

 whereas in M. laurentica the ventral spinules in the male are sepa- 

 rated on each side by an interval from the lateral spinules (fig. 4) . 



The furca offers one of the most distinctive characters by the 

 presence in both sexes of a very conspicuous dorsal crest which runs 

 somewhat obhquely along the upper side of each ramus and ends in 

 a projecting point below which the dorsal seta is inserted (fig. 5). 

 In the male the inner border of the furca is convexly expanded and 

 smooth. In the female there is a transverse row of four spinules dis- 

 tad of the middle of the inner border. A similar difference exists 

 between the sexes in M. schmeili. 



