82 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
Development of the sporoblasts into the spore-—As noted by Biitschli 
and Balbiani! in the 2-capsuled forms (Myzxobolus), each sporoblast 
divides into 3 unequal uninucleated masses, 2 small and 1 large, des- 
tined to form respectively the 2 capsules” and the sporoplasm. 
a. Development of the capsules.—Very soon there is produced in each 
of the two smaller masses, ordinarily in the neighborhood of the nucleus 
(see above) a small, rounded, clear vacuole, distinguishable from the 
surrounding protoplasm by the absence from all points of its wall, of 
granulation, Next a small protoplasmic button forms at some point of 
the wall and advances progressively into the vacuole, crowding its con- 
tents back against the sides, so that after a time it becomes a pyriform 
body surrounded by a clear layer (the vacuolic contents) and connected 
with the protoplasm by a pedicle. Little by little the pedicle becomes 
strangulated, the pyriform body thus finally becoming free. During 
this time it has acquired a membrane, and a filament is produced within 
it, evidently at the expense of its protoplasm, although Thélohan was 
unable to follow all the stages of the process. Around the capsule 
thus formed one finds the nucleus,’ and débris of the protoplasmi& 
globule which has given birth to the capsule. The nucleus remains 
most frequently attached to the capsule, but sometimes it becomes 
separated and is found engulfed in the sporoplasm. During develop- 
ment the capsules have no fixed direction, orientation taking place later. 
b. Development of the sporoplasm.—The third mass becomes the sporo- 
plasm. Very early 2 nuclei, generally near together, are seen. They 
persist to maturity. Thélohan was unable to determine whether these 
exist primitively in the sporoblasts (which would then contain 4 nuclei 
instead of 3, as Biitschli supposes) or whether they result from 
division. 
c. Development of the finished spore.—The spores, until now rounded or 
oblong, very soon assume their definite and characteristic shape and 
acquire an envelope. The tail is folded against one side of the spore, 
becoming straight only after the rupture of the pansporoblast mem- 
brane, which latter persists a rather long time. 
 Biitschli for MW. miilleri; Balbiani for M. eilipsoides (see pp. 218, 223). 
2 Not rarely, especially in Myxobolus ellipsoides, 3 to 8 capsules are found. The 
constant association with each of a nucleus shows that their formation takes place 
in the usual manner. In this case the [pan]sporoblast without doubt incloses an 
-abnormal number of nuclei. Sometimes it even seems probable that a single spore is 
‘formed instead of 2 (Thélohan). [It would be exceedingly interesting to ascertain 
whether in these cases the number of rejected nuclei is correspondingly less. 
Unfortunately, at present nothing is known on this point. | 
' 8Thélohan here remarks that in a preceding work (Compt. Rend. Acad. Sci. Paris, 
1889, crx, pp. 920-1, and Annal. de Microgr., 1890, 11, p. 210) he considered these nuclei 
as belonging to the sporoplasm and attributed to them a different origin, an errer 
which a study of the development has rectified, 
