102 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
In some seasons the short minnows are quite commonly affected with this parasite, 
as I have observed in previous years, and as I am informed is the case bj- Mr. Viual 
N. Edwards, who has had a long and extended experience in observing our coast 
fishes. I am indebted to Dr. E. L. Mark for assistance in obtaining some of the liter- 
ature of this interesting subject, especially Biitschli’s excellent paper. 
The following is a ijartial bibliography of the PsorosiJermkv : 
1. Lunel aud Claparede : Histoire naturelle des poissons du bassin du L6man. 
2. Dujardin : Histoire des Helmiuthes, pp. 643-645, 1845. 
3. Leydig : Archiv fiir Auat. und Physiologie, 1851, pp. 221-223. 
4. LieberkThn: Arcbiv fiir Anat. und Physiol., 1854, pp. 1-24; 349-368. 
5. Balbiani ; Compt. Rend. Acad, des Sci., t. 57, pp. 157-161. 
6. Balbiaxi; Legons sur les Sporozaires, 1884. 
7. Gabriel: Berichteder schles. Gesellsch., 1879, pp. 26-33. 
8. Butschli : Beitriige znr Kenntniss der Fischpsorospermien. Zeits f. wissensch. Zool., xxxv, pp. 
629-651, Taf. xxxi, 1881. 
9. ZsCHOKKE ; Archives de Biologie, vol. V, Appendix, Vers parasites d’ean douce, 1884. 
10. WiERZJSKi: Zool. Anz., No. 278. Abstract in Journal Royal Mic. Soo., 1888, p. 4, pp. 230-231. 
11. Vallentin : Zool. Anz., No. 292, pp. 622-623. Abstract in Journal Royal Mic. Soc., 1839, p. 1, 
pp. 75-76. 
EXPLANATION OP PLATE XXXV. 
1. Cyprinodon variegatus, with excrescences caused by Psorosperms, one on right side and another on left 
side showing above outline of back, x 1|. 
2-3. Psorosperms with supplemental retractile bodies behind the polar vescicles. In Fig. 3 there are a 
few small retractile globular masses near the posterior end. 
4. An individual treated with osmic acid, showing pores at the apices of the polar vescicles. 
5-6. Specimens lying on the edge, showing the rounded elevated ridge which follows the edge. 
7. Specimen treated with acetic acid. A nuclear body is deiined back of the polar vescicles. 
8. Diagram of transverse section, showing lenticular shape of psorosperms. 
9-11. Specimens treated with concentrated sulphuric acid ; 9, with a few refractile bodies and one 
thread exserted ; 10, an example with both threads exserted and a number of small refractile 
globules; 11, a specimen in which the plastic fluid interior is aggregated into a single refract- 
ile body; a thread also appears at the end oxiposite the polar vescicles. 
12-13. Polar vescicles with their threads, liberated from the body of the psorosperms after treatment 
with concentrated sulphuric acid. Nos. 2 to 13 all highly magnified. 
14. Calcareous bodies found in the abnormal tissue associated with the psorosperms. x 200. 
15. Three of the same, with a few psorosperms. Sketch made from material that had been subjected 
to the action of potassic hydrate, x 400. 
16. Psorosperms in place, (a) nests of psorosperms ; (&) section of a blood capillary ; (e) connective 
tissue. Sketch made from a section of decalcified abnormal tissue. 
