326 THE AQUARIAN NATURALIST. 



less embryo (PL VI. fig. 7, a), and might be taken 

 for an Infusorial form of life, swimming about by 

 means of a broad ciliated disk. How long the micro- 

 scopic atom keeps this shape we know not, nor the 

 mode in which it is transformed into the second 

 aspect under which it shows itself (PI. VI. fig. -7, b), 

 in which condition it is recognizable under a figure 

 somewhat like its proper self, about a line in length, 

 offering as yet only four segments bearing lateral 

 oars, although its head and eyes are quite discernible, 

 as well as one small pair of antennse. 



As growth advances, other segments show them- 

 selves successively, and these are always found to be 

 developed in one spot, namely between the last-formed 

 segment and the tail, or rather the tail-bearing ring 

 which terminates the body; and as they by degrees 

 are perfected, they develope from their sides the lateral 

 oars, which now become the locomotive agents, and 

 the creature gradually attains the appearance seen in 

 the next figure (PI. VI. fig. 7, c). 



By constant repetitions of the same procedure, more 

 segments and more oars progressively are added from 

 behind to those in front (PI. VI. fig. 7, d), until the 

 animal, at length promoted to its perfect form, con- 

 tinues to grow longer as new segments show them- 

 selves, till it acquires the complement allowed by 

 Nature in its adult state. 



Such is, in brief, an outline of the process ; but 

 there yet remains wide scope for any one, whose 

 leisure or whose opportunity affords the means of 

 adding to our knowledge on a subject so important, 

 and as yet almost in its infancy. 



