[cooper] TREMATODES FROM MARINE FISHES 199 



free-swimming miracidia, distributed throughout the soft tissues of 

 the whole nymph from the head-region to the tail. The eggs, obviously 

 extruded from the worm and resembling in every way those yet in 

 the uterus of the latter, were found to contain living miracidia. Notes 

 made at the time show that a typical specimen gave the following 

 measurements: Length, 0-079; maximum width, 0-050; diameter of 

 operculum, 0-018; length of miracidium, 0-071. These are somewhat 

 greater than those given above, but this is due to the shrinkage of 

 the latter during the dehydrating and clearing processes, for my notes 

 give as measurements of fresh material from the flukes from the gall- 

 bladder of the Shiner: Length, 0-066-0-070; width, 0-038-0-040; 

 diameter of operculum, 0-017-0-021. Furthermore, it was recorded 

 that this encysted worm closely resembled those from C. catostomus 

 and Fundiilus diaphanus menona and gave the following measurements : 

 Length, 1-10; width, 0-37; diameter of oral sucker. 0-11, of aceta- 

 bulum, 0-17. This nymph host, which is possibly an intermediate 

 one for this species of trematode, was later diagnosed by Mr. 

 Clemens as Blasturus cupidus Say ("Rearing Experiments and 

 Ecology of Georgian Bay Ephemeridse," in: Contributions to Canadian 

 Biology, 1911-'14, Fasc. II, p. 120), while owing to the absence of in- 

 sufficient literature the fluke was at that time placed in the genus 

 Halicometra. Two other Mayfly nymphs of the same species were 

 found to contain similar worms and many free eggs. 

 26. Cryptogonimus chyli Osborn. 21. 



Stomach, intestine and pyloric coeca of M. dolomieu; coeca of 

 Amhloplites rupestris; and encysted in small M. dolomieu, Amhlo- 

 plites rupestris and No tropis hudsonius (Dewitt Clinton), a Minnow. 

 The largest adult specimens at hand measure: From the Black 

 Bass, (1) 0-96 X 0-18, (2) 0-86 X 0-29; from the Rock Bass, 1-15 

 X 0-13. The smallest Black Bass, in the intestine of which was 

 found an example of this species, was 24-5 in length, while the smallest 

 worm containing eggs was from a 47mm. Rock Bass and measured 

 0-41 X 0-12. A very thorough examination of small Black Bass of 

 all sizes, from those just hatched to adults, showed that the encysted 

 worms were to be found only in those ranging in length from 9mm., the 

 size when they take their first food, to 35mm. The cysts, them- 

 selves, are elHpsoidal in shape and range from 0-20 X 0- 14 to 0-28 X 

 0-22. Most of them are situated in the musculature along the sides 

 of the body from the eyes to the caudal fin, but a few are to be found 

 just beneath the skin of the gill-covers and branchiostegals, on the 

 visceral organs, in the coelomic cavity and in the liver. The earliest 

 stages of the worm (Fig. 19) are easily recognized, even before they 

 are removed from the cysts, by their characteristic black "eye-spots" 



