294 THE AQUARIAN NATURALIST. 



tube constructed by the parent Annelide ; they are of 

 a rusty-yellow colour, and when once recognized are 

 easily procurable for the purposes of the vivarium. 



These worms usually lay their eggs during the 

 months of March and April ; but this is a rule by 

 no means of stringent application. The embryos de- 

 rived from these eggs, when first hatched, give no 

 indication whatever of the form they will subsequently 

 assume, and might easily at first be mistaken for the 

 larvae of Zoophytes or of Medusae, which they exactly 

 resemble as they swim rapidly about by means of 

 innumerable cilia distributed over the surface of their 

 almost microscopic bodies; but they are not long in 

 revealing their real nature. They soon appear per- 

 ceptibly elongated, and something like a head and 

 tail becomes distinguishable, the former being recog- 

 nized by the presence of a pair of eyes resembling 

 bright red specks. 



The progress towards a worm-like form now rapidly 

 advances, and the body becomes distinctly divisible 

 into four zones or segments ; in front there is a semi- 

 circular flattened head bearing the eye-spots ; to this 

 succeeds a broad segment covered with cilia, that 

 still constitute the locomotive apparatus; then a 

 narrow segment devoid of cilia ; and, lastly, the tail 

 or terminal segment, which is densely ciliated. 



In the course of a short time a fifth segment is 

 seen gradually making its appearance in the shape of 

 a narrow ring, interposed between the terminal seg- 

 ment and the last segment but one of the larva above 

 described. We beg the reader's special attention to 

 the circumstance here marked in italics, for until 



