336 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Internal organa . — The mastax is oblong, truncate at either end; its circular end appears in a 
ventral view in front of the broad pectoral notch of the lorica. To its sides are attached two pro- 
jecting glandular bodies (fig. 65, gl.). The trophi are nearly or quite symmetrical. The internal 
organs partake in their arrangement of the peculiar asymmetry that appears in the lorica. The 
stomach lies to the right of the middle; its walls contain many large, spherical, light-yellowish, 
refractive granules. The ovary lies to the left of the stomach, not ventral to it. The lateral canals 
of the left side lie ventral to the ovary and present three flame cells, one at the side of the posterior 
end of the mastax, one at the side of the anterior end of the stomach, and one just in front of the 
contractile vesicle. The two halves of the mucus reservoir (fig. 65, to. r. ) are pushed widely apart, 
the left one being much the larger. The brain is of the usual form; on its dorsal surface it bears 
the eye, formed of a large clear sphere, embedded in a deep red cup. 
Measurements . — Length of body, 0.17 to 0.18 mm.; of toe, 0.12 mm.; total, 0.29 to 0.30 mm. 
History . — This species was described by the present author in 1894. A description and figure 
are given by Stenroos (1898) and a figure by Jennings (1901). 
Distribution . — In America: I have found this species in the following localities: East Harbor, 
Lake Erie, near Sandusky, Ohio; Lake St. Clair; West Twin Lake near Charlevoix, Mich.; Grave- 
yard Pond on Presque Isle near Erie, Pa.; Huron River at Ann Arbor, Mich. Kellicott (1896) 
records this species from Sandusky Bay, Lake Erie; Hempel (1898) from waters connected with 
the Illinois River at Havana. 111. 
In Europe: Lake Nunnijarvi, Finland (Stenroos. 1898). 
31. Rattulus bicuspes Pell (pi. viii, figs. 73-76). 
Synonyms: Mastigocerca bicuspes Pell (1890); Mastigocerca spinigera Stokes (1897). 
Distinguishing characters. — This very peculiar species maybe known by its short, plump body, 
high arched dorsally; by the unarmed anterior edge of the lorica; the very prominent lateral 
antennae, protected by stout spines; and by the long toe, longer than the body. 
External features . — The body is very short and thick, the ventral line nearly straight, while 
the dorsal line is a high arch. The highest part of the body is a little behind the middle; thence 
it falls off suddenly to the foot, there being in some cases even an inward curve just above the foot 
(fig. 73). The anterior part of the lorica, or head-sheath, is not strongly marked off from the 
remainder, though a slight constriction can sometimes be seen behind it (fig. 73). There are no 
teeth or spines at the anterior margin. Considerably to the right of the dorsal middle line is a 
ridge, which is fairly prominent in living individuals, but seems less noticeable in preserved spec- 
imens. It is rather broad and reaches from near the anterior edge to a point some distance behind 
the middle of the lorica (fig. 75). It is transversely striated (i. e., it contains transverse inirscle 
bands). 
Corona . — The corona is of the usual character, the only point deserving especial mention being 
the antenna-like processes. There are five of these, as in B. latus Jennings, R. multierinis Kelli- 
cott, and R. capucinus Wierz. & Zacli. The median dorsal process is stout and club-shaped; on each 
side of this, and nearer the ventral side, are two slender processes close together (fig. 75). 
Antennae. — The most peculiar feature of this species are the lateral antennae. These are in 
the usual position, on the posterior part of the lorica, near the dorsal side. Each forms (or is 
accompanied by) a large, sharp spine, with its basal part enlarged. According to Stokes (1897), 
fine setae may be seen just in front of these spines, close against them; these I have not seen. 
The dorsal antenna is in the usual position, a short distance behind the anterior edge of the 
lorica. It lies just to the left of the striated area (fig. 75). 
Foot . — The foot is a small, short structure, arising as a continuation of ventral part of body. 
Toes. — There is one main toe (representing the left toe of Diurella); this is longer than the 
body and is nearly straight. The rudimentary right toe is very small and curves toward the main 
toe, its tii> lying against the latter. 
Internal organs . — This species is not a favorable one for the study of the internal organs, these 
being crowded together in the short, thick lorica in such a way as to make it very difficult to dis- 
entangle them. There seems in any case to be nothing calling for special remark. The trophi 
(fig. 76) are rather stout, and of the usual unsymmetrical form, the left side being much better 
developed. 
