TEREDO XAVAL1S IN NOVA SCOTIA — MURPHY. 3G3 



K>tie quarter to half a millimetre, it enlarges little by little, until 

 it reaches a diameter of five millimetres and more ; as regards 

 his length, and consequently that of the tube which incloses him, 

 we have sometimes found it to be thirty to forty centimetres. 

 He never goes upward more than half way between the flow 

 and ebb of the tide ; although the teredo is thus, for a short 

 time, partially above the water, yet it appears that the wood 

 holds a sufficient amount of moisture to sustain his life tempo- 

 rarily. 



" The researches of Kater have still further shown, what had 

 already been remarked by Sellius, that the Teredo can hibernate 

 in the wood, and that it is those individuals, thus preserved/which 

 in the spring go through with all the phenomena of reproduction 

 — i. e., the formation of eggs, fecundation, development, and ex- 

 pulsion of the young. 



" The part of the external integument? which constitutes the 

 mantle deposits a calcareous matter, forming an interior lining 

 to the gallery in the Wood (fig.12. f.) Between this calcareous cas- 

 ing and the body of the animal there remains a space sufficient 

 to prevent any inconvenience, at least during the act of respira^ 

 tion, for it is possible that when the Teredo absorbs water, which 

 serves for respiration, his body is distended, and fills exactly the 

 calcareous tube. The form of this tube, secreted little by little.. 

 corresponds exactly with that of the gallery, which has been 

 slowly perforated in the wood ; it has the appearance, also, of a 

 series of rings placed one against the other. As the animal pro- 

 gresses a new ring is added to those which existed before, so that 

 when the tube is closed at its extremity by a calcareous film, its 

 length represents the total length of the animal, (fig. 12 ; b to c) 

 Among the segments of the tube, those which are nearest the 

 surface of the wood are the oldest and hardest; in the interior 

 of the wood, where the gallery ends (fig. 12, g), the calcareous 

 ring, newly formed, is at first soft, flexible, and of slight consist- 

 ency ; later, it becomes solid, and closes up the tube, as has been 

 remarked by Sellius. 



" The calcareous tube, once formed, constitutes for each Teredo 

 his own abode, where he isolates himself from his companions. 



