285 



neighborhood of Lake Superior, said that the animal 

 died from this obstruction. The calculus was perfectly 

 impacted in the urethra, so as to prevent the egress of 

 the bloody urine which distended the bladder.* 



Mr. John Green made some remarks upon the micro- 

 scopic structure of certain fish scales he had recently 

 been examining; he showed them to be of bony struc- 

 ture, which he considered to have an important bearing 

 on classification. 



Dr. Gould alluded to some recent observations in 

 France in relation to the reproduction of Arachnides, or 

 rather their power of producing fertile eggs, though com- 

 pletely isolated from the male. Blanchard found that 

 the genital apparatus of the female was composed of two 

 ample tubes to which the ovarian crypts were attached. 

 These serve as reservoirs in which the seminal fluid accu- 

 mulates, through which the eggs pass and are impreg- 

 nated ; but which is not exhausted by one ovulation, 

 serving for many subsequent occasions. Blanchard 

 therefore concludes that one coupling is necessary, and 

 serves for several years. M. Delfraysse had in like man- 

 ner invoked anatomy to settle the question. He like- 

 wise finds the two tubes and the fecundating liquid ; but 

 states that he has found two little glandular bodies be- 

 tween the ovaries and tubes, which secrete the fertilizing 

 fluid. He therefore concludes that the animals are her- 

 maphrodite ; — that the seminal fluid is furnished at the 

 time of laying eggs, and not kept in store ; and that no 

 copulation is absolutely necessary. Dr. G. remarked 

 that there was evidently room for further anatomical 

 research, and did not see how the latter conclusion com- 

 ported with the well-known organization of the Arach- 

 nides as males and females. 



* In the account of Calculi from the bladder of an ox, upon page 213 of this 

 volume, it should have been stated that their composition was nearly pure silica. 

 Secretary. 



