SPOROZOON PARASITES OF FISHES. 205 



10 to 14 turns (fig. 26, 28, pi. xxi). In young spores the valves are quite thick and may 

 be seen at the edges as a pale border to the spore, but in mature spores they are thin 

 and almost invisible. Young spores are shorter (i2/() and wider (7.5/1) than the 

 mature spores and the polar capsules are not so long (6/0 . They lengthen out as they 

 approach maturity. When young, the nuclei stain with great difficulty, if at all. The 

 sporoplasm occupies all the space at the large end of the spore. A large vacuole is nearly 

 always visible in the sporoplasm. There are also dense areas and from i to 10 nuclei. 

 (Fig. 20, 28, pi. XXI.) The nuclei are unstained in figure 29, plate xxi. There are some- 

 times seven greenish-blue nuclei (fig. 28, pi. xxi) and three rather irregular dark-blue 

 bodies between the polar capsules. It is not possible to be sure that this (10) is the 

 maximum number as some of these are ill defined. A number of spores have their 

 nuclei attached near the large end of each polar capsule, thus identifying them as the 

 "polar capsule" nuclei. Probably the remaining four belong to the sporoplasm. It is 

 not possible to recognize the "wall nuclei" at this stage, and the "resting nuclei" of 

 the pansporoblast are doubtless lost. 



CHLOROMYXUM FUNDULI. 



The Chloromyxa which have been obser\'ed in the muscle of other fish (p. 208) are not 

 identical to that found in Fundulus. C. quadratum, which resembles the latter, has 

 myxospores measuring 6/i in diameter by 5/! along the polar axis, while the Chloro- 

 myxum of the Fundulus measures 7.511 in diameter and 6fi along the polar axis and 

 differs in shape. The spore of C. quadratum, when seen in line with the polar axis, has 

 the sides deeply concave, and in the other plane it is more pointed. The polar capsules 

 are also much shorter. They also differ in the relation of the spore to the pansporoblast 

 and in the pathological effects. (For description of spore of C. junduli see p. 208.) No 

 reference to a myxospore of this character has been found by the writer. The name 

 C. funduli has therefore been applied to this species. 



The myxospores of C. /j(«(f)(/i have been encountered in but one fish. If the myxo- 

 plasm occurs in other preparations, it has not been possible to identify it, although many 

 suspected myxoplasms exist. It is not very probable that they are at all uncommon. 

 They do not take up a particle of such stains as we have employed. The single slide 

 containing this species is a smear preparation made from the diseased flesh of a fish 

 which died in jar no. i of the experiment reported on page 196. It is stained with 

 Giemsa stain. 



The muscle of this fish is in an advanced stage of decomposition. When the fresh 

 slides were examined no myxospores were noticed, being difficult to see without a stain, 

 but the sporoblasts were observed without recognizing their importance. 



Bacteria are present on the slide but lacking in the muscle fibers. The decadence 

 of the muscle must in this case be ascribed to the Chloromyxum, which is abundant in 

 the hypertrophied muscle. The muscle is full of cavities containing unstained myxo- 

 plasms and sporoblasts which are identical in appearance to those of many other prepara- 

 tions of diseased Fundulus. While this case introduces the possibility that many of the 

 Fundulus cancers may be caused by Chloromyxum funduli, it gives very substantial sup- 

 port to the agency of Sporozoa as the cause of these diseases. Since Chloromyxum and 

 Myxobolus are not uncommon in muscle tissue, double infections are to be expected. 

 But having failed to encounter myxospores of the Chloromyxum in over 100 stained 

 19371°— vol 33—15 14 



