PACKARD.| REPRODUCTIVE HABITS OF BRANCHIOPODIDA. 423 
The indirect factor of the red color! (or green, of others) of Eubran- 
chipus [ assume to be microscopic organisms contained in the soil of the 
ponds, primarily and gradually acted upon by quercitannic acid or tan- 
nates and humus. 
I have grave doubts whether to regard the pale races, set B, as par- 
tially starved individuals, since their nourishment consists of organic 
matter contained in the mud. The latter is taken up in precisely the 
same manner as known in the European Branchipus stagnalis, i. e., by 
striking with the occipital part of the head against the mud, thus filling 
through the agitated mud the ventral median canal between the bran- 
chipeds, and thence by gradual paddling, the mud will pass therefrom 
toward the head and mouth. The contents of the alimentary system, 
as examined, also correspond with this manner of feeding. They will 
never partake of any kind of food thrown into the water. (The pale 
races had not reached sexual maturity had they not had food enough.) 
Sesquichloride of iron did not indicate even a perceptible trace of 
quercitannic acid in the clay-water of the isolated pool, but such was 
the case with the brownish clear water of the surrounding ponds in- 
habited by the normal large and red Eubranchipus. 
The slightly milky water of the isolated pool owes its color to finely 
suspended clay-particles, and, I should judge, although I have neglected 
to microscopically examine the same, contains comparatively more or- 
ganic matter, adhering to the inorganic particles, than the clear water 
of the other pools. This is contrary to the assumption that the pale 
races were partly starved individuals. deli 
I rather draw the inference, that we here have both, a difference in 
quantity, and quality of nourishment, the former preponderating, the 
latter indifferent as to color. The contents of the alimentary system of 
Branechiopods are for the greater part a fine soft magma of mud inter- 
mixed with oil-globules, the latter being the secretion of the wall-glands 
of the canal. 
Very likely specimens living in water with finely dispersed mud or 
clay, have less trouble in getting their food, the nourishment being more 
uniform and already so fine that it needs not to be masticated or sepa- 
rated from coarser particles.” 
Remarks on the cephalic sceute or Kopfschild.—Is not the larval cephalic 
scute® (in our form ¢ of set B, preserved in the adult) a rudiment of 
the two valves of the Estheridw? In that family two or three thoracic 
segments serve for the insertion of the bivalvular duplicature. 
Mode of copulation of pale race of Eubranchipus vernalis.—The copula- 
tion between males of set B with females exhibiting the two forms of 
claspers illustrated by figures 61, A, B, lasts from 3 to 4 ninutes, but many 
unsuccessful attempts to accomplish the same are usually made, often end- 
ing with the escape ofthe females, owing to the check caused by the crossed 
-claspers. In both the red and white race the attempts were never made 
1 An interesting note on chlorophyll and protection of colorless cells as an absorbent 
of certain ligkt-rays is to be found in Amer. Nat. March, 1880. 
2Mr. E. P. Austin—Amer. Nat. X (Aug. 8, 1876), page 508—mentions that in March 
he obtained 28 different species of Dytiscide from a small clay-pit which had been 
filled with water. Some of the species occurred in immense numbers. 
Hermaphroditism, Amer. Nat. March, 1380, page 200.—Hermaphroditism seems to 
be a thraldom necessary at the outset, but from which all living things are seeking 
to escape. (Sexual differentiation in Epigawa repens, by Lester F. Ward, A. M.) 
’Spangenberg, loc. cit., page 14, Taf. I, Fig. 1, and also Dr. Carl Claus, ‘‘ Zur 
Kenntniss des Banes und der Entwicklung von Branchipus stagnalis und Apus cancri- 
formis.” Gdéttingen, 1873, Taf. II, Fig. 5, D. P.; also same author in “ Beitriige zur 
Kenntniss der Entomostraken.” Marburg, 1860, I. Heft; also Dr. A. 8S. Packard in 
“‘Phyllopod Crustacea,” and same author in “Cave Fauna of Utah and descr. of new 
spec. of Crust.” 
