KANSAS ACADEMY OF SCIENCE. 



69 



pectinate fringe. Caudal rami slender; six to seven times as long as broad j 

 fully equal in length to the two and a half segments immediately preceding. 

 Each ramus bearing six finely-plumose setse, and on the outer side, at about 

 one-fourth its length from the base, a short transverse row of six to eight 

 point-like spines, similar to those which constitute the pectinate fringe of the 

 last abdominal segment. Of the four apical setse, the first is much shorter 

 than the furca, the fourth still shorter, the second fully three times as long 

 as the furca, and the third about half as long as the second. The webs of 

 the second and third extend well toward the ramus. First antennse, seven- 

 teen-jointed, scarcely reaching the third body-segment. (Nearly reaching 

 the fourth segment in the male.) Labrum usually with eleven teeth. The 

 armature of the swimming-feet is as follows: 



(a.) Outer branch. 



Basal ioint f exteriorly, one spine. 

 Uasai joint ■) interiorly, " seta. 



TiT!jji„ ;„:„* f exteriorly, one spine. 

 Middle joint.. I i^jg^j^^l^; .. ^»(^ 



( exteriorly, two spines. 

 Apical joint... < apically, " setae, 

 (interiorly, ' ' setaj. 



First foot. 



(6.) Inner branch 



s^^^U^int {f^;'Z 



Middle joint., j?^'' 



armed. 



seta. 



ex., unarmed. 



two sette. 



ex., one seta. 



Apical joint... <j ap., one spine, one seta. 



in., three setse. 



Older branch. 

 Basal joint. 



fex., one spine, 

 ■(in., '' seta. 



Middle joint.. {F;; one ^Pi-. 



Apical joint. 



Outer branch. 



ex., two spines. 



ap., one spine, one seta. 



in., three setje. 



Second foot. 



Inner branch 



Basal joint lf^-'"° 



•' ( in., om 



Tit:AA\„ ■„;„4 fex, unarmed. 

 Middle joint.. I i^;^^^ggj^ 



armed, 

 e seta. 



fex., one seta. 

 Apical joint... < ap., one spine, one seta. 

 I^in., three setse. 



Third foot.— Like second foot. 

 Fourth foot. 



Inner branch. 



Basal ioint I ^^■' ""^ spine. 

 Basal joint <^^^ one seta. 



,,.,,, • - 4 (ex., one spine. 

 Middle joint... I i^'^^Q^t^ 



fex., two spines. 

 Apical joint... ■< ap., one spine, one seta, 

 (^in., three setse. 



narmed. 

 one seta. 



Basal joint j?^;-^' 



i«-i.q.qi<. ;^;„t f ex., unarmed. 

 Middle joint.. I i^Jt^^ggt^ 



I ex., one seta. 

 Apical joint... ^ ap., two spines, 

 (in., two sette. 



Inner of the two apical spines of the inner branch of the fourth foot half 

 the length of the outer. Fifth foot composed of two joints, of which the 

 apical is well developed and about half as wide as the basal ; the basal bear- 

 ing at its outer angle a rather short seta, the apical bearing one rather short 

 and one long seta. Ovisacs small, broadly elliptical, with major axes par- 

 allel to the sides of the abdomen, which they partly cover. Each ovisac con- 

 tains from thirteen to twenty-two (usually sixteen to twenty) large eggs. 

 Animal yellowish white, or sometimes particolored in yellow and white. (In 

 the male, the yellow first abdominal segment contrasts with a lighter-colored 

 segment preceding and following.) Ovaries often colorless, but becoming 

 darker as the eggs approach maturity. Ovisacs varying from dark blue-gray 

 in the earlier to almost colorless in the later stages of the development of the 

 contained eggs. 



Length of animal, exclusive of caudal setse, 1.11 mm. (Male, .92 mm.) 



