ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 83 



den HolocfpJinli\ CallorliyDclius unci CIiii)ucra besitzt das Mannchen vor deni Pterygopodium jederseits 

 einen sehr verwickelt crebauten Apparat. Derselbe besteht aus eiuer Tasche, in welcher mehrere, 

 Knorpel enthaltende, niit Widerhaken verseliene Stiicke hervorgestreckt werden konnen. Ich fand 

 diese Tasche bei Callorhynchiis n:it Samen gefiillt. Auch bei dieser Gruppe der Elasniobranchier 

 wird demnach der Samen vor der Begattnng nach aussen gebracht. Wie freilich hier die Begattung 

 stattfinden wird, lasst sich vorlanfig nicht angeben. The essential thing is that Schneider declares 

 to have found sperm in the bag in Acanthias and in the pouch of the pelvic appendages in Callo- 

 r/iyiic/i/is; certainly no proof is given, but we shall have to suppose that Schneider has really found 

 the spermatozoids. Whether these ha\'e been numerous, that is to say, whether the bags in question 

 really can be said to have been filled with the semen, of this we know nothing with certaint\-, and 

 we can — in my opinion — not yet in any way put it down as an indubitable fact that the glandular 

 bag of the Plagiostomes is a reservoir that has to be filled with the semen and by the copulation to 

 eject it. Nothing is said of the way, in which the filling of the bags in question should take place. 



I have unfortunateh- not been able to get a paper by Ha swell (Notes on the claspers of 

 Heptanchus. Proc. Linn. Soc. N. South Wales, vol. 9, P. 2, p. 381). 



During the time between the appearing of the present essa}- in Danish and this translation I 

 have received a paper by H. C. Redeke (Onderzoekingen betreffende het Urogenitaalsystem der Se- 

 lachiers en Holocephalen. Acad. Proefschrift etc. Helder 1898) in which (p. 77) after a representation 

 of what till then was known regarding the appendages and their function, the author declares that 

 he has himself found numerous spermatozoa in the «mixipterygoid bag:; ') in one single specimen 

 among many examined specimens of AlHsfcliis vulgaris. He calls, however, attention to the fact that 

 the bag was not filled, which fact he explains by supposing, either that the animal during its agony 

 might have emptied the bag, or rather that these animals will copulate, as soon as the bag is filled. 

 An observation bv another observer, respecting a male Rafa clavafa that had ejected an abundance of 

 semen > through the dilated appendices, can scarcely be regarded to be of any value, as there is no 

 proof to the effect that the ejected fluid in reality was semen and not the secretion from the gland. 

 Finalh' is quoted an observation by Professor M. Weber, which observation the author thinks may 

 be used to explain, in what manner the filling of the glandular bag might be brought about. I shall 

 give the proper words of the author, and else abstain from advancing my strong doubt of the fact: 

 <iDeze (Prof. Weber) nam waar, hoe een groote Rog {Raja clavafa) rondzwemmende in een der bassiu.s, 

 plotseling een groote wolk, vermoedelijk sperma, loosde en vervolgens, misschien reflectorisch, heftig 

 met zijn mixipterygien begon te zwaaien, die daarbij een pompende beweging schenen nit te voereu. 

 Het is niet onmogelijk, dat 00k in de natnur, al is de omweg een allerzonderlingste, het sperma eerst 

 in een groote hoeveelheid geloosd en gelijktijdig door de mixipterygien in den zak opgezogen wordt* 



i| The appellation of IMixipterj-gium, which has of late often been used in stead of the objectipnable . Pterygopodium > 

 of Petri, is due to Gegenbaur (Das Flossenskelet der Crossopterj-gier etc. Morph. Jahrb. vol.22, 1S95, p. 146, uotei)). 



