ROTATORIA OF THE UNITED STATES. 
341 
the figure shows it to be in the same position as the tooth of Rattulus scipio Gosse (q. v. ) . The main 
toe is not quite half the length of the body, and is furnished with two substyles, of which one is 
long and S-sliaped. 
The peculiarly formed head-sheath, the sharp lateral spine at the anterior end, and the long 
substyle are considered the characteristic features of this species. 
Length of body, 0.80 mm.; thickness, 0.06? mm.; length of toe, 0.138 mm.; of the longest 
substyle, 0.05 mm. 
The animal was found in Lake Nurmijarvi in Finland. 
Rattulus roseus Stenroos (?) (pi. xv, fig. 137). 
Synonym: Mastigocerca rosea Stenroos (1898). 
This species has a close resemblance to Rattulus longiseta Sclirank (Mastigocerca bicornis 
Ehrb. ) . from which it is said by Stenroos to differ chiefly in two points. One is in the form of the 
body — in this species broadest in the anterior half of the body, while Rattulus longiseta is said by 
Stenroos to be broadest in the middle. This, however, is a character which will by no means 
always hold for R. longiseta; it is not at all rare to find specimens that are broadest near the head. 
The chief point of difference is, however, that the two teeth at the anterior edge of the lorica are 
said to be on the ventral side, in place of on the dorsal side, as in R. longiseta. 
This difference is unquestionably sufficient to justify the formation of a new species. But 
when we consider the relation of the anterior teeth in other Rattulidce to the dorso-dextral striated 
area or ridge, and to the method of movement of the animal, as described in the first part of this 
paper, it is difficult not to question the presence of two teeth like those of Rattulus longiseta Schrank 
on the ventral anterior margin of the lorica. In Stenroos’s figure (reproduced in fig. 137, pi. xv), 
which seems clearly a dextro-ventral view, if we suppose that the shorter tooth is seen through the 
transparent head of the animal (which may sometimes be done) , the figure would agree throughout 
with R. longiseta Schrank. Stenroos states, however, that he has compared the two species, and 
that they are different. 
Length of body, 0.336 mm.; thickness, 0.086 mm.; length of toe, 0.218 mm.; of the substyle, 
0.05 mm. 
This species was found by Stenroos in Lake Nurmijarvi, in Finland. 
Rattulus brachydactylus Glasscott (pi xiv, fig. 130). 
Synonym: Mastigocerca brachydactyla Glasscott (1-S93). 
I copy herewith the entire account (as well as the figure) of this species. 
“ S%>. ch.. — Body irregularly cone-shaped; head lumpish; toe style-like, short, straight, no sub- 
styles. no ridge. 
“Allied to M. stylata \Rattulus stylatus Gosse], but broadest at the head; body an irregular 
cone, puckered into constrictions, but not gibbous in the middle; the toe straight and finely pointed, 
only one-fourth the length of the body; no substyles; gait wobbling. 
“ Habitat. — A pond, County Wexford.” 
It is, of course, not entirely evident from the above description that this animal is really one of 
the Rattulidce at all, and it is doubtful if the description and figure are sufficient to permit of its 
recognition if found again. 
Rattulus antilopseus Petr (1890). 
This may have been Diurella tigris Muller, though from the figure and description it is impos- 
sible to be certain. The description given by Petr is as follows; 
“ Body cylindrical, somewhat narrowing toward both ends; foot broad, one-jointed, ending in 
two toes bent toward each other sickle- wise; these about half the length of the body. At the base 
they are provided with two pairs of little spines.” (Petr, 1890, p. 222). « 
The figure resembles a poorly drawn contracted specimen of Diurella tigris Muller, with the 
toes strongly bent in opposite directions and crossing one another. This condition of the toes, on 
which the new species seems to be based, is almost certainly due to distortion. A species so 
inadequately described and figured can only be dropped. 
a For the translation of this diagnosis from the original Czech language, in which it was written, I am indebted 
to Prof. George Rebec, of the University of Michigan. 
