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Show 444 MR. J. B. SUTTON ON HYPERTROPHY. [May 5, stoma cysticolum the female has rudiments of testes, but no male generative aperture. In those forms in which the individuals inhabiting one cyst are not different in appearance, the sexual organs have a different structure ; each individual is here androgynous, but differs from the free living androgynous species in that the testis is developed only on one side of the body, and there is but one generative aperture. In Myzostoma pentacrinus, however, there are small remnants of the other testis, but no second male aperture. The testis also, as in the dioecious forms, is a small compact gland. Since the testes of the dwarf males are fully developed on both sides, we must not regard the hermaphrodite species M. pentacrini and M. deformatum as transitional between the typical hermaphrodite forms and those that are dioecious, but the latter must be derived independently from living* lorms. In M. cysticolum the male and female are found associated in a common cyst, and increasing in size with the growth of the cyst perforate the arm-joints of their host together. The growth of the cyst is, of course, caused by the presence of the parasite; the female deposits her eggs within the cyst, and the young embryos, after they have abandoned the cyst and lost their ciliated coat, associate together in pairs, and bore their wav throu»h the arm-joints. In both the sexual development begins with the appearance of testes ; but in the female the testes disappear entirely, or leave but a minute rudiment, when the ovaries make their appearance in addition l. Among the most striking examples of the peculiar value of hypertrophy in this direction must be mentioned the curious malformed generative organs which occur in the cattle known as "Free-martins." Hunter was one of the first to carefully investigate the condition of the reproductive organs in these cases ; and the valuable dissections he made, now in the Hunterian Museum, are striking monuments of his inquisitiveness in this matter. Stock-breeders hold the opinion that when a cow produces twins, one a male and the other a female, the latter is unproductive (imperfect). This is very frequently true, but by no means always so. An imperfect calf under these conditions is known as a Free-martin or Martin-heifer. Careful comparison of the detailed descriptions of the dissections of these malformations, and similar cases in Sheep and Goats which have come under m y observation, show most conclusively that in these cases we have to deal, not with any one malformation common to all examples of Free-martins, but rather with instances in which both sets of organs have attempted to attain a functional condition, with the result that both have failed to reach it. In some of these cases the Wolffian ducts have advanced many stages towards making a fairly complete set of efferent ducts for the testicles, and the calf approaches somewhat to a bull-calf. In other instances the Miillerian ducts have made greatest progress, and a estUowf?^ 'f!" R B^dd"rd f0r drawinS m? atteuti0* to these inter-esting observations of Dr. von Gruff. |
