. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Fig. 102. which could have brought to this part the seer e tion of the testicles. Lastly, and this proof is still more conclusive, on examining carefully the under surface of the abdomen of a male, he discovered at its base, i. e. at the point where it is inserted into the thorax, between the aper- tures of respiration, and at the part correspond- ing to the vulvary opening of the female, two very small orifices, placed in a transverse fissure, which he ascertained to be the true outlets of the male apparatus, fie found
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Fig. 102. which could have brought to this part the seer e tion of the testicles. Lastly, and this proof is still more conclusive, on examining carefully the under surface of the abdomen of a male, he discovered at its base, i. e. at the point where it is inserted into the thorax, between the aper- tures of respiration, and at the part correspond- ing to the vulvary opening of the female, two very small orifices, placed in a transverse fissure, which he ascertained to be the true outlets of the male apparatus, fie found in the inte- rior of the abdomen two cylindrical dilated vessels, which he determined to be the testes. (Fig. W2,b,b.) These two organs open into two long, slender, tortuous, excretory canals (c), which terminate at the two orifices of which we have spoken (a), but without the appear- ance of any superaddition of a firm or horny part that can be compared to a penis. From this description it is certain that what has been regarded as the act of copu- lation, has been only preli- minary, and that the intro- duction of the extremity of the maxillary palp of the male into the vaginal aper- tures of the female was forthe mere purpose of opening the oviducts in order that the ac- tual coitus should be effect- ed with facility and with- out doubt instantaneously ; which explains why no ob- server has hitherto witness- ed the act.* The remarkable sexual differences which obtain in the araneae are not found in other arachnidans. Thus in the scorpions the maxil- lary palps have a similar organization in both sexes, being terminated by pincers, both in the male and female, (Jig. 84, b.) The external aperture of the male apparatus is placed behind the thorax, and manifests itself by the presence of a valve formed by two semi- circular pieces (fg. 84, c.) The internal struc- ture of these organs is but imperfectly known. Treviranus believes that he could distinguish the testicles which term
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