OF TWO SPECIES OF CYPRIS. 237 



Whilst intently regarding the agitated mass which had been set 

 free, we saw one of the hooked ends protrude and gradually draw 

 itself out from the rest with an extended spiral motion, such as 1 had 

 never witnessed before. This process was very gradual, and at 

 last stopped. It then began to withdraw itself, until, arrivmg at a 

 certain stage in its backward progress, it again stopped, paused, 

 and then began to move forwards again. I had been using a 

 quarter-inch. This I changed for a one-eighth, and again watched 

 its backward and forward movements, which kept on for twenty 

 minutes. The motion was in a spiral direction, and the hooked 

 end seemed to agitate the fluid in its neighbourhood. Previous to 

 this, it had been no uncommon thing to see portions of the cara- 

 pace drawn towards them. I am unable to say whether this 

 action w^as caused by capillary attraction, or by the presence of 

 ciliate processes at present unseen by us. These portions of the 

 carapace became impaled at the end, and were spun round with 

 great velocity. This is remarkable when we consider the dis- 

 parity of size. 



We thought we should like to trace the spermatozoa down the 

 efferent ducts. I therefore extracted the spermatheca with the 

 duct attached. These zooids were a lively lot, and we had no 

 difficulty in tracing the vibratory motion to the base of the sper- 

 matheca — spermathecal-aperture — and a short way down the duct, 

 when it was lost to view. I then extracted some of the zooids from 

 the duct. We found that a bundle of zooids of various sizes passed 

 down the duct. I extracted two in their entirety — viz., with their 

 hooked and corkscrew terminations. These I covered with a 

 cover-glass, adding distilled water, and thus was enabled to time 

 the length of their vitality as one hour and ten minutes, after 

 which time all motion ceased. 



The spermatozoons are the carriers of the sperm. In imma- 

 ture specimens the sperm can be seen within the sheath. The 

 length of a spermatozoon barely exceeds the one-fortieth of an 

 inch. If fresh, broken spermatozoa be examined with a one- 

 sixteenth immersion, it will be seen that sperm will escape by 

 emission, or it will protrude. If the former, it has a tendency to 

 run or frill off at the point where it is broken. If the latter, we 

 find a thin, membranous substance enclosing the sperm lining the 



