ROTATORIA OF THE UNITED STATES. 
83 
thick point (fig. 7), yet this is comparable in texture merely to the “'tail” of Copeus pachyurus, rather 
than to a projection of the lorica, such as occurs in a Brachionus. 
A little above the two lateral longitudinal folds above mentioned there is a broad longitudinal 
depression, above which the arched dorsal part of the body is much less in width than the ventral 
part. This depression is indicated by a strip of deeper shading along the side in fig. 7. 
The corona (fig. 8), is of the typical Notops character, resembling in all essential details that 
of N. clavulatus, just described, and in many respects very closely that of N. brachionus, as figured by 
Western (’90). A nearly circular outer ciliary wreath is interrupted on each side by an ear-like 
unciliated projection, with a deep notch in front of it; there is also a short ventral uuciliated region. 
Within this wreath are three curved styligerous prominences about the buccal funnel; these corre- 
spond in position to the three main prominences in N. clavulatus and, I should judge, to the middle 
dorsal and the two ventral prominences shown by Western (’90) in N. brachionus. The exact number 
of styles on each of these prominences was not noted, so that the figure does not attempt to be 
accurate on that poiut. At the side of the middle prominence, between it and the lateral prominences, 
are two thick styles or antennae, taking the place of the two bunches of small cilia to right and left of 
the middle prominence in N. clavulatus. The ciliated buccal funnel descends from within the three 
prominences; some distance within there are on the sides two small elevations, each with a number of 
stiff setae extending transversely across the buccal groove, exactly as in N. clavulatus. As previously 
mentioned, the coronal surface is very nearly a direct continuation of the ventral surface of the animal, 
so that a ventral view permits a thorough study of the corona. A thick dorsal antenna projects from a 
notch in the anterior dorsal margin of the lorica, exactly as in Brachionus. Lateral antennae were 
not observed. 
The foot is short and thick, and is quite without annulations. It is scarcely at all extensible^ 
varying little in length, so far as observed. The two toes are very inconspicuous, at times retracted, 
so as to be quite invisible. Each ends in a minute tube, through which at times a thick mucus is 
exuded, by means of which the animal adheres to objects with which it comes in contact. A broad 
canal can be traced from each toe to a group of small glands at the base of the foot. The trophi 
(fig. 9) are malleate, agreeing in all essentials with those of K. clavulatus as figured by Wierzejski (’93) 
and Gosse (’56). Each uncus contains five broad blunt teeth. On each side of the mastax, situated 
apparently iu some portion of the alimentary canal, there is — in many specimens at least — a bright red 
spot, the two making almost the appearance of eyes. The large brain, triangular in side view, carries 
at its posterior dorsal poiut the single large red eye. The other internal organs were not studied. 
The egg is carried by the mother, attached just above the base of the foot, in exactly the position 
in which a Brachionus carries its eggs. 
Notops pelagicus feeds upon the unicellular algae which float in the clear waters of the lake and form 
the primary food supply of almost all the water organisms. Thus, if we consider the organisms of the 
lake as forming a chain, of which these unicellular algae, deriving their sustenance directly from the 
inorganic constituents of the water, are the first link, while the highest carnivorous fish are the last, 
this rotifer forms a part of the second link, standing in relations of dependency only to the primal 
source of food supply. 
Notops pelagicus is noteworthy for its bearing upon the classification of the Rotatoria. It seems 
to belong unquestionably to Notops, and to be more closely related to the soft-bodied members of that 
genus; yet it has an evident partial lorica. In spite of this lorica, it clearly does not belong at all 
with those loricate members of the (former) genus Notops that have recently been separated off by 
Weber (’98) as Gastropus. Its relations are not with Gastropus stylifer, G. minor, and G. hyptopus, but 
with Notops clavulatus and N. brachionus ; at the same time, it is evidently related to the species of 
Brachionus. I believe with Lund (’99) that the Hydatinadre are to be grouped naturally with the 
Brachionidae, and that the softness or stiffness of the cuticula (upon which depends whether the animal 
is called loricate or illoricate) is a character of little significance in classification. 
It is to be noted that in the two important papers that have appeared most recently on the 
Rotatoria, the species of the genus Notops have been divided in the same manner, but that the name 
Notops has been left with a different division in each case. Both Weber (’98) and Lund (’99) separate 
Notops clavulatus and N. brachionus on the one hand from N. hyptopus, N. minor, and N. stylifer ( pygmceus ) 
on the other. But while Weber leaves the name Notops to the former group, calling the others Gas- 
tropus, Lund gives the name Notops to the hyptopus group, relegating the others to Hydatina. I have 
followed Weber, for reasons given under the discussion of the genus Gastropus. 
N. minor Rousselet; N. pygmceus Caiman. — See Gastropus, under Loricata. 
N. laurentinus Jennings. — See Proales laurentinus Jennings. 
