333 



COPEUS PACHYUKUS (MaLE). 



By F. R. Dixon-Nuttall, F.R.M.S. 

 ' (Communicated hy O. Western, F.R.M.S., Octoher 20th, 1893J. 



Plate XV. 



On the 1st August, 1893, I had a quantity of female 0. 

 pacliyurus in a small zoophyte trough, and had the good fortune 

 to see one lay two small eggs, which I at once thought would 

 be males, and on looking carefully over the trough found 

 several others. I removed a quantity of the females, leaving 

 only a few, and put fresh pond water into the trough each day. 

 On the 7th I found two full-grown males, and on the 8th there 

 were at least half-a-dozen. I was unable to keep them alive 

 long, for on the 10th not one could be found. I cannot say that 

 this is any test as to the length of their natural life, as the 

 weather was so exceedingly hot I was unable to keep the 

 temperature of the trough as low as it would be in the ponds, 

 and I had several eo^2:s that did not hatch. 



In general outline they are very much like that of a young 

 female, are restless little fellows, and, unlike the females, 

 seldom withdraw their auricles, but keep swimming in a some- 

 what spiral mode. 



The brain, as in the females, is three lobed and of the same 

 shape (thongh I am of opinion the two smaller lobes are a little 

 more pointed, and in some cases slightly more granular or 

 opaque). Each sac is filled with numerous cells, which give 

 the covering or skin the appearance of being beautifully and 

 evenly marked with a fine hexagonal pattern. This 1 have 

 noticed is the. case in the females too. 



The occipital antenna stands at the base of the long lobe of 

 the brain, and I also find this in both genders. 



The eye is seated on a small ganglion, which rests between 

 the two side or small lobes, and under the long, narrow neck of 

 the centre lobe of the brain, 



JouRN. Q M. C, Series II., No. .34. 24 



