THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 183 



HaMtat. — Siibcntaiieous tissue of all regions of tlie ho^j oi Notro]^is 

 merialops Raf. (red finned minnow) taken in Black River, Lorain County, 

 Ohio, (3 miles above Lake Erie, September 1, 1890 (also October 5, 1891; 

 see below). Collector, Mr. L. M. McCormick. Identification by Dr. D. 

 S. Jordan. 



With this species of fish were taken Noturus miurns, Catostomus teres, 

 and Moxosioma macrolcpidotum, and, in the immediate neighborhood, 

 Ictalurus and Roccus. None of these, however, were affected. 



Effects. — The epidermis of the fish is sometimes marked by dark 

 purplish blotches. Scales are absent from the surface of the cyst in 

 most cases, although a few were observed quite loosely attached to one 

 of the larger clusters. All of the fishes appeared to be in fair condition. 



Mr. McCormick has kindly furnished me the following additional 

 information : 



The fish were taken in the pool formed by Day's Dam, near the center of Sheffield 

 Township, Lorain County, Ohio. Although he has diligently explored the streams 

 of Lorain County for material for his " Descriptive List of the Fishes of Lorain County, 

 Ohio,"^ he has never seen X. 'meyalops infested by this parasite except in this very 

 limited locality. The same day that specimens were first secured there he seined 

 Black River thoroughly from Elyria to below Day's Dam (distance 10 miles), but saw 

 no other diseased specimens. In spite of the admitted fallibility of negative results, 

 he believes this parasite to be restricted to a very narrow geographical range. Fish 

 first taken September 1, 1890 (about a dozen); a few more October 5, 1891 (the first 

 time of seining the pool that year). 



13. Genus et sp. incert. PI. 7, fig. 4. 



Psorosperms of Gasterosteus acuJeatus, Lieberkiihn, 1854, Muller's Arcliiv., pp. 

 9-10, 22, 24, 354-7, pi. 2, fig. 28, pi. 14, figs. 9-12. 



The following observations by Lieberkiihn relate to a puzzling form 

 found on Gasterosteus aculeatus (stickleback). His remarks are to me 

 somewhat obscure, and I am not certain that I always understand 

 his meaning. For that reason the translation is a literal one. 



[Page 9] I am still in entire ignorance as to what becomes of the psorosperms ot 

 Gasterosteus. In the skin of this fish Gluge found cysts filled with entirely 

 structureless granules which had a marked similarity to those of the Gregarines. 

 Johannes Miiller has confirmed this discovery. I investigated about 100 cyst-bearing 

 8i)ecimen8 selected from a corresponding number of healthy sticklebacks. Among 

 10 fishes there was, in the spring, about 1 available; in late autumn, on the con- 

 trary, only 1 in about 100. The cysts varied greatly in size; the largest attract 

 .attention at once, the smaller are only to be discovered upon close examination. 

 They have a very irregular form, mostly rod-shaped, and contain ordinarily the 

 structureless granules mentioned by Gluge. A few contained bodies with more defi- 

 nite structure and characters, reminding one of the psorosperms, for which reason 

 I will so name them. They are all nearly globular and somewhat smaller than the 

 ordiuary psorosperms; they consist of a transparent membrane, within which I have 

 observed 3 kinds of contents, namely, in some a single small globule which is not 

 large enough to come in contact with the membrane by its upper surface; in others 

 lay, between the surrounding membrane and the upper surface of this 

 [Page 10] small globule, a small mass of exceedingly fine granules; in still others 

 the globule appeared to have divided, as 3 or 4 smaller globules were 

 present. Several of the smaller cysts contained a far more finely granular mass than 



'Bull. 2, Oberlin College, Ohio. 



