ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 8l 



or Spinax), when he supposes the appendices to be organs for intromission and retention Hke the 

 Penis of the Dog; only in a hollow these spnrs, tliorns etc., can be of importance as 

 retentive organs; it is quite evident that they are barbs that are kept stiff, as long as the dila- 

 tion of the terminal part lasts. Viewed in this way the dermal teeth on the terminal part in Scyllium, 

 PrisHuriis (and Chimcera) will also get importance, they being placed with their points towards the 

 base of the fin and raised by the dilation; they will also — although to a less degree — act as barbs. 

 When the dilation ceases, all these barbs — large and small — are laid, and thus they present as 

 small resistance as possible by the extraction from, as well as by the introduction into a hollow. That 

 the object is that they may be introduced and extracted without resistance, is very finely shown in 

 some instances; this, abo\-e all, applies to the ;hook> [Td] in Aca/it/iias] in the position of rest it fits 

 so elegantly into the spoonlike ventral terminal piece (Tv) as to remind of a surgical instrument'). 

 All the appendices are moreover adapted for being thickh' smeared with the viscid secretion of the 

 glandular bag, and accordingly being made smooth, by which an introduction into a relativel)- narrow 

 hollow may be highly facilitated. 



I think then that the structure of the appendix shows quite indisputably: i) that this 

 organ is intended for being introduced into a hollow, and 2) that it is able to fix itself in this hollow 

 by the dilation of the terminal part. In this wa\- — but only in this way — the appendix becomes 

 an organ of retention during copulation. It would a priori be the only reasonable supposition, that 

 the hollow of which the question here can be, must be the genitals of the female; b>- the observation 

 of Bolau this supposition has been made a certainty, and this gives to his observation its special 

 importance. My opinion then is, that at all events it may be put down as certain that the 

 ventral appendages during copulation serve as retentive organs in the genitals of 

 the female^). But this can scarceh" be their only function. My opinion is that they must have 

 several functions, among others to awaken the sensuality, and furthermore to open (or at all events 

 to waden) the mouths of the oviducts in virginal females, and thus secure impregnation and facilitate 

 the parturition ; and though I cannot imagine that the appendix-slit shotild form a duct for the sperm, 

 I still think it probable that the appendages in some way or other subserve the conveying of the 

 semen, so that it is not conveyed by means of the urogenital papilla of the male alone. And I also 

 suppose that the secretion of the glandular bag subserves this object. As we have seen, the secretion 

 is in all appendices not onh' evacuated through the hind end of the organ, in the terminal part, but 

 also in all instances through the opening at the base of the organ, and thus not only the genitals of 

 the female and the appendix itself, but most likely the whole immediate surrounding of the cloaca in 

 both the copulating animals will be lubricated by the secretion. The consequence of this will be 

 that the sperm will easily be mixed with the secretion, and it may readily be supposed that this 

 mixing may have a stimulating influence on the spermatozoids, or act as gathering and conveying 



■) Gegenbaur, who does not at all mention the function of the appendix, says of these parts in Acanihias (I.e. 

 p. 452j: Das Verhalten beider Stiicke ahnelt den verdeckten Haken, wie .sie als chirurgische Instrumente gebraucht werden*. 



2) The old, before quoted obsen-ation in Aristotle gains by this view very much in trustworthiness: There are 

 those who assert that they have obser\-ed that some of the Selachians hang together behind like the Dogs>; and it lies near 

 to suppose that it is this kind of < hanging together , that is suggested by Pennant (Brit. Zoology-. New. Ed. 1812, Vol. Ill, 



p. 112) of the Skate: -. several of the males pursuing one female; and adhere so fast during coition, that the fishermen 



frequently draw up Ijoth together, though onh' one has taken the baits. 



The Tngolf-Expedition. II. 2. ^^ 



