48 BULLETIN OF THE LABORATORIES 



is clearly seen and all the details of the water vascular system may be 

 made out with ease. The lateral vessels are tortuous canals, while 

 upon them are seated beaker cells, the flask-shaped base of which con- 

 nects directly, by means of a curved tube of less diameter, with the 

 main canal. The mouth of the flask is directed downwards and 

 has a small opening near which is the point of insertion of a long 

 cilium Avhich extends upward into the flask, where it is constantly in 

 motion. There seems to be no reason to doubt that by means of 

 these beaker-cells the vascular system is in communication with the 

 perivisceral cavity. The foot is comparatively slender and has, aside 

 from distinctly cross-striate muscles, two large foot glands which open 

 in the ends of the rather long dagger-shaped claws. A pair of fine 

 bristles springs from the dorsal surface of the last segment of the foot. 

 The following measurements were taken : 



No. I. lorica .22 mm. long. No. 2. .22 No. 3. .24 



" .14 mm. wide. .14 .15 



foot .06 mm. long. .06 — 



claws .07 mm. long. •. 07 .072 



jaw capsule .06 mm. long. .06 .048 



Found in Minnesota during the whole summer among water plants. 



EUCHLANIS AMPULIFORMIS, Sp. )l. 



{Plate II, Fig. 3.] 

 This species, which deviates toward Salpina, is smaller than the 

 above and, in outline, is somewhat flask-shaped. The back is cari- 

 nate and the flat ventral plate is excavated posteriorly with a cordate 

 opening. The head is produced and densely hairy below. The 

 maxtax is small, but the cervical eye is very large. The nuclei of the 

 ovary are very Conspicuous, although the egg is not as large in propor- 

 tion as in the above. The foot is four-jointed and the claws are elon- 

 gated and somewhat curved. The lorica is .16 mm. long, the claws 

 .08 mm. Another individual measured .20 mm. and the claws were 

 .12 mm. long. This species was seen but twice, June i8th, 1884, 

 in Minnesota. 



POLYARTHRAEA. 



The family includes the two genera, Triarlhfa and Polyarthra. In both 

 genera the foot is wanting and appendages of the sides of the body take its place. 

 The body is not segmented except anteriorly and the form is not definite. The 

 genus first mentioned has two lateral and a ventral appendage, while in Polyarthra 

 the appendages are collected in groups upon the opposite sides. In both generp, 

 the egg is carried about as in Anutxcs^ 



