INVEETEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 721 



oviduct is given off from it at riglit angles, and just behind tlie 

 central portion ; it opens on to the fifth pair of legs. On taking 

 a Ci/mothoa 13 mm. long we find, in addition to the ovaries, 

 testes, the vasa deferentia of which can be easily followed into the 

 penes. So that the hermaphrodite arrangement seems tolerably 

 certain ; tracing the matter still further, we may observe animals 

 when they are taken from the brood-pouch of their mother, as BuUar 

 docs not seem to have done ; in such, the external genitalia are not 

 developed, and the tissues of the internal organs are still in an 

 altogether embryonic condition ; four regions may, however, be made 

 out, of which three go to form the testes, and one the ovary ; two 

 efferent ducts, oviduct and vas deferens, may also be made out, 

 though they are as yet very short. In the next stage the testes were 

 enormous as compared with the ovary, and the two penes were 

 developed ; in the succeeding stages, the male organs were observed 

 to be in functional activity, and ova were developed in the peripheral 

 portion of the ovary. As affecting the supposition that the " testes " 

 observed by Mr. Biillar were " spermatophores," it is of interest to 

 note that Mayer expressly states that he was able to make out the 

 different stages in the development of the sperm ; in the anterior 

 l^ortion of each vesicle there were small cells, not to be distinguished 

 from epithelium, which were connected with a number of larger 

 vesicular cells, and succeeded by sperm-cells, with very short tails, 

 and then by bundles of still riper sperm, exactly similar to those 

 found in the terminal portion of the vas deferens. Notwithstanding 

 the presence of the tail, Mayer, no more than Bullar, was able to 

 observe any movement of the sperm ; and this is esijecially remark- 

 able, inasmuch as the parasitic Cirripedia are the only members of 

 the great group of the Crustacea in which mobile sperm-cells have as 

 yet been observed (always excepting Limiilus, which has so many 

 points of affinity to the Arachnida). 



From what has been said, it will be seen that the young individuals 

 appear to be males, and the older forms females. 



The view of Bullar that the ancestors of the parasitic species 

 were dioecious is supported by the investigations of Mayer, who 

 remarks further that in other Isopods he has observed indications of 

 hermaphroditism, inasmuch as in some females of the genera Cirolana 

 and Conilera, he has observed a filament passing just like a vas 

 deferens, to the seventh segment, together with rudiments of the 

 testes. Interesting as this observation undoubtedly is, the c[uestions 

 which it raises must for the present remain unexi)lained. 



Asellus cavaticus.* — Dr. Max Weber, having had an opportunity 

 of examining this remarkable form at Bonn, takes the occasion to 

 point out certain characters which distinguish it from A. aquaticus, 

 and which have hitherto escaped observation. In correlation, probably, 

 with the absence of eyes, the olfactory organs are much larger in 

 A. cavaticus ; in the female the superior autenufe are nine-jointed, and 

 the last three joints are each provided with an olfactory process, 



* ' Zool. Aiizeiger,' ii. (1879) p. 233. 



