349 



forming a group. They are perfectly distinct from the surrounding 

 tissue of the testis, and stain very darbly. It cannot be decided on 

 the material I have whether these bodies are eggs or not. I can only 

 say that they very much resemble young eggs and there is a striking 

 likeness in structure between them and the true eggs taken from an 

 ovary. 



Although I am perfectly aware that the above notes are not as 

 satisfactory as could be Avished, partly owing to the state of preser- 

 vation of the specimens which certainly are good enough as objects for 

 a museum, but not for anatomical researches. I think, however, that 

 they ought not to be withheld because they contain certain facts which 

 seem to be of great interest. These might be summed up as follows : 



1) the supernumerary genital j) orifices« on the third pair of legs in 

 the male Parastacus Hassler i Faxon, and fifth of the female, are closed, 



2) both sexes can be discerned on an examination of the outer parts, 



3) in both sexes a pair of supernumerary 'genital ducts (thus 4 ducts 

 in all) are present, corresponding to those of the opposite sex, 4) it 

 seems at least possible that the masculine genital gland contains fe- 

 mine elements (eggs), althoug I do not think it probable that these 

 can be fully developed, still less be of propagative use. 



Thus it may be said that in Parastacus Hassleri a partial herma- 

 phroditism is prevailing, but male and female organs are not functio- 

 nary in the same individual, neither are ripe elements of both sexes 

 produced by the same specimen. The hermaphroditism could thus be 

 called rudimentary. It can also be supposed, with all probability, that 

 the conditions and structure of the reproductive organs of the other 

 species 0Ï Parastacus in which two pairs of genital »orifices« have been 

 observed are similar to those described above. The same might also 

 be the case with the species nCheraps plehejus(( from Adelaide, the 

 male of which von Martens has found to be provided with sexual 

 orifices also on the third pair of legs. The author mentioned did not 

 however find any rudiments of oviducts, but that might depend upon 

 the state of preservation of his material. Ortmann^ and Faxon^ 

 which have written later about species of Clieraps do not mention any 

 thing about the genital organs or openings of these forms. Our know- 

 ledge about this subject is thus very restricted, and it is not easy to 

 draw any conclusions at present. I should however not be surprised 

 if further investigations would reveal facts of a similar kind concern- 

 ing other Decapoda Macruna. 



A couple of times I have believed to have seen rudimentary ducts 



3 Zool. Jahrb., Abth. Svst. VI. 1892. 

 M. c. 



