32 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



caused by large, vividly blue cells which occur among the appendicular 

 muscles, and also as a layer applied to the dorsal side of the intestine 

 throughout its length, and to the ventral side in the thoracic region. 

 The axis, or corm, of the appendages is colorless or pale green, some- 

 times contains blue cells, and in addition has large cells, less numerous 

 than in the male, with yellow, orange, or brown oil globules. Endites, 

 exites, and endopodite and exopodite are colored as in the male. 



The ovary appears yellowish white to light blue, depending on the 

 stage of development of the large oocytes, and can be plainly discerned 

 through the body wall from the fourth or third abdominal segment to 

 the eighth or seventh thoracic segment. 



The color pattern of the ovisac is characteristic of the species. The 

 proximal thu'd of its wall is colorless to pale yellow; the middle third 

 yellow, orange, or pinkish yellow; about two-thirds of the posterior 

 third is bright blue, and the tip, about 12^ percent of the total length, 

 is white or faintly blue. In the case of living females, the species 

 can be easily recognized by a conspicuous blue area, which can be 

 seen by the unaided eye, on the posterior half of the ovisac. 



The cement glands appear brownish yellow to pale brown under low 

 magnification, and have a characteristic arrangement. Eggs, within 

 the ovisac, vary from dull yellow to yellow-brown. 



The walls of the abdomen are nearly colorless except for the black 

 intestine and the conspicuous layer of blue cells along the dorsal side 

 of the intestine. 



The cercopods are colorless in most, but sometimes are pale yellow, 

 pale orange, or colorless with yellow or pinkish yellow borders. 



Discussion: The number and arrangement of the dorsolateral lobes 

 on the thorax of the female is probably a good specific character in 

 raiany species of Branchinecta. In fact, they are conspicuous in size, 

 shape, and arrangement in many species of other genera, but have 

 rarelj'^ been mentioned or depicted in taxonomic descriptions. They 

 have been present in every specimen of Br. cornigera, new species, and 

 also in every specimen of Br. packardi Pearse and Br. lindahli Packard 

 (as revised by Shantz)^ that I have examined. In Br. coloradensis 

 Packard (as revised by Shantz)^ and in Br. paludosa (O. F. Miiller) 

 they are conspicuous in populations from some localities and absent in 

 those from other localities. 



Other characters of some taxonomic value are the pulvillus and the 

 dorsolateral bosses. The pulvillus, or swollen area on the median 

 side of the basal article of the antenna of the male near its junction 

 with the head, is present and conspicuous in some species of 

 Branchinecta and absent, or barely represented, in others. When 

 present, it is covered with minute spinules, verrucae, or denticles 



• See under heading of "Remarks," page 34. 



