324 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Toes. — The main toe is a nearly straight rod; in the adult (fig. 54) about half the length of the 
lorica; in a young specimen (fig. 53) it is about two-thirds as long as the lorica. There are two 
“substyles” (one doubtless representing the right toe); the longer of these is about one-fourth 
the length of the main toe. 
The most peculiar feature of the foot and toes in this species is a spur-like point which 
extends backward from the distal end of the foot, at the base of the toes. It is shown in figs. 53 
and 54 ( sp .) as well as in the figure of this species given by Levander (1894). This spur is not 
found, so far as I am aware, in any other species. When the toe is extended straight back from 
the body the spur is not visible. 
Internal organs. — The few specimens at my command did not permit a study of the trophi. 
Otherwise the internal organs seem to offer nothing worthy of special mention. 
Measurements. — length of adult without toe, 0.3 mm.; length of toe, 0.14 mm. : total, 0.44 mm. 
History. — Rattulus macerus was described by Gosse (1889) from a single, partly disorganized 
specimen. He did not notice the anterior tooth on the lorica (which is very inconspicuous), and 
he describes and figures the lorica as thicker in its posterior part. But in his specimen the head 
and part of the internal organs had flowed out in a disorganized mass, leaving the anterior part of 
the lorica collapsed-, so that it is natural that the posterior half should have been a little thicker 
than the anterior. Otherwise his description agrees well with the specimens I have found. 
Levander (1894) described this animal as Mastigocerca fusiforrnis n. sp., and gave a very 
characteristic outline figure. His figure shows the spur at the base of the toe, but he did not 
notice the inconspicuous tooth at the right anterior margin of the lorica (his figure shows a view 
from the left side, where this would not be seen). It seems to me that there is not sufficient 
difference between the accounts of Gosse and Levander to justify considering them as describing 
different species. Gosse’s description is a little less full than Levander’s, though both give 
only brief general descriptions — neither of them mentioning (for example) the tooth or the very 
characteristic spur (though Levander shows the latter in his figure). 
Scorikow (1896) describes this species without a figure. He considered R. macerus Gosse and 
R. fusiforrnis Levander to be the same, but incorrectly included R. gracilis Tessin as a synonym. 
Distribution. — I found four specimens of this species in material taken from the marshy part 
of Lake Erie about “ The Cottages,” on Long Point, Canada. Gosse (1889) met with it in water 
from Woolston Pond, Hants, England; Levander (1894) in ponds and pools in Finland; Stenroos 
(1898) in Lake Nurmijarvi in Finland; Scorikow (1896) in a swamp near Kharkow in Russia. 
21. Rattulus multicrinis Kellicott (pi. vi, figs. 55-58). 
Synonym: Mastigocerca multicrinis Kellicott (1897). 
Distinguishing characters. — This species is distinguished at once from all others by its broad, 
regularly ovate form. From Rattulus latus Jennings, the only species which resembles it at all in 
general appearance, it is markedly distinguished by the symmetrical form of the posterior part of 
the lorica. (Compare fig. 57 of R. multicrinis with fig. 65 of R. latus.) 
External features. — The lorica is broadly ovate in dorsal or ventral view, widest in the middle 
region, narrowing a little in front to the capacious liead-sheath and tapering rapidly and regularly 
behind to the foot. The form is remarkable for the almost complete lack of the asymmetry which 
is so striking in most of the Rattulidce. 
In side view (fig. 56) the lorica swells out strongly on both the dorsal and ventral sides. 
There is in this species nothing comparable to the usual ridge or striated area. 
The anterior part of the lorica or head-sheath is not sharply separated from the rest of the 
lorica, though there is a wide, shallow constriction in its base. The head-sheath is marked by 
numerous longitudinal folds and the anterior edge is crenate, each fold projecting a little as a 
rounded point. In the dorsal middle line there is a large, prominent triangular point projecting 
considerably beyond the rest of the lorica. When the head is retracted (fig. 58) the liead-sheath 
becomes folded and the anterior opening nearly closed. The anterior part of the lorica then has 
a striking resemblance to the same portion in Rattulus eapucinus Wierz. & Zach. (pi. vi, fig. 59) 
and R. cylindricus Imhof (pi. vu, fig. 62) , indicating that R. multicrinis is closely related to these. 
Corona. — This species shows the more complicated type of rattulid corona with especial 
clearness (figs. 56, 57). The following parts may be distinguished: (1) Two large half circles of 
