of the Organs of Pilularia globulifera. 497 
Fig. 32. Another view of a union of sporules in their first stage. 
Fig. 33. A union in its second stage; the mother-cell is now visible :—magni- 
fied 150 times. 
Fig. 34. An abortive sporule in the third stage :—magnified 120 times. 
Fig. 35. An abortive sporule after it has acquired its outer coat, but before 
the coat has become thick enough to obscure the lines on the spo- 
rule. 
Fig. 36. An abortive sporule in its final shape. 
Fig. 37. Fertile sporule in the third stage. "Three of the sporules are rup- 
tured; the other is enlarged :—magnified rather more than 100 
times. 
Fig. 38. A union of sporules from a fertile theca, in which all four of the spo- 
rules are ruptured. 
Fig. 39. Is the same as fig. 37, but more advanced ; the sporule is consider- 
ably enlarged and of a pyriform shape; the mother-cell is consider- 
ably dilated. 
Fig. 40. A more advanced sporule. There is a considerable deposition of 
matter around the upper part of the sporule, and also a beginning 
at the larger extremity. The three ruptured sporules have disap- 
peared :—magnified 54 times. 
Fig. 41. A still more mature sporule. 
Fig. 42. A ripe sporule in its theca removed from the involucrum. The 
action of the water in which it was examined on the gelatinous 
covering, and its being removed from the pressure of the other 
thecae, have caused the theca to swell and assume a roundish figure, 
a, One of the four visible unions of ruptured sporules, 
