578 W. BLAXLAND RENHAM. 



situated just below the cell membraue ; moreover, even in 

 the earlier phase observed, there is a larger more centrally 

 placed vacuole, the outline of which is at first not specially 

 distinct. This vacuole gradually increases in size, but I 

 could not determine whether this results from the union of 

 the smaller vacuoles with one another, which appears pro- 

 bable. With this increase of the vacuole the cytoplasmic 

 envelope becoiues thinner and loses its 'Mioneycomb " ap- 

 pearance, etc. (fig. 11). At first, and for some little time, 

 the outline of the vacuole, though distinct, exhibits no pecu- 

 liarity ; but after a time it becouies more definite, and 

 appears as a gradually thickening wall, which then becomes 

 refringent. This refriugency (fig. 12) commences to be evi- 

 dent at one side, sometimes on the side next the nucleus, 

 but as often at any other point. This refringent arc gradu- 

 ally extends so as to become crescentic (fig. 13), the ends 

 always thinner than the central region ; and by a continua- 

 tion of this procedure the central vacuole becomes completely 

 surrounded by a circular refringent ring (fig. 14). These 

 stages were particularly well exhibited in a fully mature 

 individual examined in November. 



This ring now continues to thicken, so that the vacuole 

 becomes constantly reduced ; and as it does so, the ring- 

 seems to become differentiated into irregularly concentric 

 layers, alternately more and less refringent; in this way the 

 fi^brils of the thread are established (fig. 15). But mean- 

 while the contents of the vacuole have also become con- 

 centrated and refringent along transverse lines, giving rise 

 to curved loops passing from one side of the ring to the 

 other ; and in this way the " coil " represented in fig. 9 is 

 brought about. 



In this history there are many points of resemblance to 

 the development of a nematocyst within a cnidoblast; and at 

 an early stage the likeness of the young linocyte to a fat cell 

 is very evident. The fibrillation of the " ring '^ is not evident 



tions to an anitt-hoid cell; or at least to some indifferent cell witli a centra 

 nucleus. 



