340 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
DESCRIPTIONS COMPILED FROM OTHER AUTHORS. 
35. Rattulus curvatus Levander (pi. xiv, fig. 129). 
Synonym: Mctstigocerca curvata Levander (1894). 
This species is distinguished l>y the long, cylindrical, slender body, very strongly curved, and 
by the prominent movable spine at the anterior margin of the lorica. The rather long head-sheath 
is set off from the body, as in most species, by a slight constriction. The toe is about one-third the 
length of the body. Other details are not given by Levander. 
Measurement f§. — Length of body, 0.176 mm. ; thickness of body, 0.033 mm.; length of toe, ' 
0.055 mm. 
Distribution. — This species was found by Levander in Finland along the shores of the island 
Lofo. 
36. Rattulus dubius Lauterborn (pi. xiv, fig. 133). 
Synonym: Mastigocerca dubi a Lauterborn (1884). 
This marine species was described briefly by Lauterborn from a single specimen found near : 
Helgoland. The body is rather short, with a slight constriction between the head portion and the 
remainder. At the anterior end, both dorsally and ventrally, a triangular projection of the lorica. j 
The toe about half the length of the body; without substyles. Length of the body, 0.11 mm.; 
thickness in front, 0.032 mm.; length of toe, 0.058 mm. Other details not given. 
DOUBTFUL SPECIES, SPECIES INSUFFICIENTLY DESCRIBED, AND SPECIES WRONGLY ASSOCIATED 
WITH THE RATTULID/E. 
1 
Rattulus unidens Stenroos (?) (pi. xv, fig*. 135). 
Synonym: Mastigocerca unir&is Stenroos (1898). 
I give in the following a translation of Stenroos's description of this animal. His account of 
the internal organs is omitted, since these show nothing peculiar. 
“ The body is elongated, cylindrical, scarcely narrowed posteriorly. The head portion is set 
off from the body by a line, and its length is somewhat less than its width. On’ the ventral side it 
appears to be cleft backward to the boundary. On the dorsal side there is a chitinous ridge or 
dorsal keel, which is extended forward as a tooth. At its broad basis, at the boundary of the head 
portion, a small opening is visible. Dorsal setie, on the other hand, I have not found. The foot 
joint is about as long as broad, narrowed posteriorly, and furnished with three spines or toes, the ; 
medial one of which is more than half as long as the body, while the two lateral ones are bristle- I 
like, equal in length, and somewhat curved. 
“ Length of the body with the foot-joint, 0.26 mm.; thickness of the body, 0.06 mm.; length of 
the toe, 0.125 mm.; of the substyles, 0.034 mm. 
“The rotatory organ is furnished with about four short and thick finger-like papillae. The 
large, crescent-shaped red eye is furnished with a refractive lens, and lies upon the large, oval brain.” j 
(Stenroos, 1898, p. 145). 
It will be noticed that this species agrees with Rattulus gracilis Tessin in the single tooth 
at the anterior end, and approximately in the body form and in the toes. Possibly it should be 
considered a synonym of the species just named. Or it may have been described from specimens 
of Rattulus scipio Gosse. It was found by Stenroos in Lake Nurmijarvi in Finland. 
Rattulus cuspidatus Stenroos (?) (pi. xv, fig. 136). 
Synonym: Mastigocerca cuspidate Stenroos (1898). 
This species bears much resemblance to Rattulus scipio Gosse, and should probably be 
identified with that species. It was described by Stenroos from a camera sketch made some time J 
before the description was written. 
Stenroos notes its resemblance to R. scipio Gosse, but considers the two distinct. The body 
is broadest in front, and gradually narrowed toward the rear. The liead-sheatli is set off by a 
slight constriction, and is furnished with a tooth which is said to rise from the right ventral side; 
