70 THE ROYAL SOCIETY OF CANADA 
C. Myxobolus notatus, sp. n.! 
Characters : Cysts as large as 3 mm. in diameter in the connec- 
tive tissue of the voluntary muscles. Spores piriform, length 17—18y, 
width 7-5-8, with a posterior extension forming a tail 5y in length 
and as broad as the spore. An iodinophilous vacuole in the amoebula. 
One polar capsule length 7, width 44. Filament 95y. 
Habitat: the blunt-nosed minnow, Pimephales notatus, Ra- 
finesque. 
The cysts cause swellings which are easily recognized externally 
on the sides or tails of the fish. The parasite was found in 6% of 
Pimephales notatus examined. It was not found in other minnows, 
Notropis blennius, and N. cornutus caught with P. notatus. 
The cysts are surrounded by a dense layer of connective tissue 
(Fig. 5, con. tis.). Inside this covering there is what appears to be a 
layer of columnar epithelial cells (epth.) between the connective 

MY x. epth. con. tis. 
Fig. 5. Myxobolus notaius, sp.n. Outer edge of cyst. myx., outer edge of 
myxosporidium; epth., epithelial layer; con. tis., connective tissue. Drawn with the 
camera lucida from a section stained in Delafield’s haematoxylin. x 2600. 
tissue and the myxosporidium. The writer is unable to explain the 
origin or significance of this layer. It shows very clearly in the sec- 
tions and completely surrounds the cysts. The apparent division 
into columnar cells and the structure of the nuclei of these cells make 
it difficult to consider it as a part of the myxosporidium. On the 
1 The author is indebted to Dr. B. A. Bensley for telling him of the existence of 
this myxosporidian. 
