6 Prof. R. Kossmann on the Ciyptoniscidse. 



freely ; but he observed exactly similar animals creeping or 

 swimming about close to the SaccuUna, and these he regarded 

 as females. He saw no genital apertures, or, indeed, genital 

 organs of any kind in them, but observed their conversion into 

 the adherent animal, which undoubtedly is of the female sex. 

 As, however, in this, in a stage which is already strongly 

 metamorphosed, the ovaries are still quite immature, the 

 female larva, according to Fraisse's own opinion, can only be 

 quite immature. Nevertheless, although he had " no oppor- 

 tunity " of observing the copulation, and did not even himself 

 see " the spermatophores adhering to the female," he is of 

 opinion that this immature larviforra female must already be 

 fecundated. " Thus, therefore," he writes, " the fecundated 

 female attaches herself, while the male retains its form and 

 probably perishes after the act of copulation." 



Evidently all that he has seen (or not seen) is opposed to 

 Fraisse's own opinion, and tends to show that the male is 

 indeed sexually mature and copulates in the above-mentioned 

 larviform stage, but that the female becoming sexually 

 mature at a much more advanced stage is also sought out and 

 impregnated by the male only in this sessile condition. 



That the male is really larviform I can positively assert 

 from careful examination of such stages. We can very dis- 

 tinctly recognize the genital apertures at the base of the last 

 pair of pereiopoda ; we find the mature testes in the trans- 

 verse section, and witness the brisk movement of the sperma- 

 tozoids. In the GryptoniscidcB, therefore^ the mature male is 

 larviform and still famished with natatory feet upon the pleon. 



That the female is coupled before its sexual maturity there 

 are no observations to show, and nothing warrants any such 

 supposition. But that on arriving at sexual maturity it is 

 sought out and copulated by the male is supported by the 

 observation of Buchholz, who writes with regard to Crypto- 

 ihir [Hemioniscus] : — " Nearly in every Balanus which con- 

 tained one of the sacceiform animals there occurred one or 

 more small, elongated, brownish animalcules" (here follows the 

 description of Rathke's Liriope-ioxm) ; as also by Fraisse's 

 own figure (Taf. xii. fig. 1), in which such a larva is shown 

 clinging to the metamorphosed female ; and, finally, by the fact 

 that, in 1872, 1 found such a male animal, as I then supposed, 

 in the Philippine Eumetor Uriopides, and in 1883 in a Neapo- 

 litan species of the same genus, three of them, and, indeed, 

 clinging fast to the female. The natatory power of these 

 males makes it very easy to understand that we do not always 

 meet with them with the females as among the Bopyridai ; 

 they probably often spontaneously quit the female, and are 



