190 Transactions. — Zoology. 



(vulva) is of various forms and sizes in different species. In connection with 

 this aperture is frequently a peculiar corneoi;s process — epigyne (f. 6^) — 

 differing more or less in structui-e in almost every species yet known, and 

 thus in most species furnishing a tangible and reliable specific character. In 

 a similar situation is the external orifice (exceedingly minute) of the male 

 seminal organs ; no external or protrusive process has ever been observed to 

 be connected with them. Experiments on the generation of spiders, made 

 with great care by our distinguished araneologist, Mr. Blackwall (" Report on 

 some recent researches into the structure, functions, and economy of the 

 Araneidea," — Report of Brit. Assoc, 1844, pp. 68, 69), go to prove con- 

 clusively that the seminal organs of the male spider (at least so far as any 

 external use or application is concerned) are in some cases wholly unnecessary 

 for the impregnation of the female, and this has led me to conjecture 

 (hypothetically) that there may be some minute ducts connecting the seminal 

 organs with the alimentary canal through which the fecundating fl.uid might 

 pass to the oesophagus, and thus be taken from the mouth by the palpal 

 organs. The discharge of the spermatic fluid in birds into the lower intestine, 

 whence it is voided by the vent, has been mentioned to me by a scientific 

 friend as a somewhat analogous case to what I have suggested. This idea has 

 received some support (in fact it was raised first in my mind) by the repeated 

 notice, in several species, of the constant application, by the male, of the 

 digital joint of the palpus to the mouth, between the times of its application 

 to the female organs. These applications were alternate and rapid, and very 

 distinctly made, and no other use was made of the palpi during the whole 

 process of copiilation. The question as to the existence of such ducts, as I have 

 supposed might exist between the male seminal organs and the alimentary 

 canal, would be one well worth the attention of insect anatomists living in the 

 tropics, where spiders of large size might easily be procured for dissection, and 

 in adult males the presence of spermatozoa might be sought for in the oesophagus 

 and mouth by means of the microscope. No European spider is perhaps large 

 enough for such an investigation to be prosecuted with much chance of any 

 certain result. Some arachnologists are of opinion that the male spider 

 collects the seminal fluid with its palpal organs from the minute orifice above 

 noted, but I am not aware of an instance in which any spider has been 

 detected in such an employment of its palpi, either during the process of 

 copulation or at any other time, nor, I believe, has any fluid ever been 

 discovered in the palpi. Mi*. Blackwall's opinion would seem to be that 

 impregnation is wholly independent of the male seminal organs or of their 

 contents, which is a jjosition contrary to all reason and analogy ; but whatever 

 may be the real facts in regard to this, it is certain that the palpi and curious 

 palpal organs of the male spider are actively used in copulation, and afford 



