. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTIVE SYSTEM OF LIMACINA 13 ture ova and spermatozoa near the gonoduct, or the presence of mature cells of both sexes along it, indicates that the animal is functioning both as male and female. Individuals of this type are called functional her- maphrodites, a name commonly used to designate this kind of repro- ductive individual among mollusks. Animals with less than half of the gonadal tissues consisting of male reproductive cells, which are classified as hermaphroditic females, can also be divided into two groups i
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTIVE SYSTEM OF LIMACINA 13 ture ova and spermatozoa near the gonoduct, or the presence of mature cells of both sexes along it, indicates that the animal is functioning both as male and female. Individuals of this type are called functional her- maphrodites, a name commonly used to designate this kind of repro- ductive individual among mollusks. Animals with less than half of the gonadal tissues consisting of male reproductive cells, which are classified as hermaphroditic females, can also be divided into two groups in a similar manner: (a) hermaphroditic females with gonads containing 50-25 per cent of male tissue, and (/?) hermaphroditic females with less than 25 per cent of male tissue in the gonad. These two types are represented in Fig. 2, E and F. As a general rule, gonads which are predominantly feminine are in a mature stage, containing mature ova and very often both mature ova and sper- matozoa. The Limacina possessing these gonads are generally larger than the masculine types. Part of a gonad with 25-50 per cent of its tissues consisting of male germ cells is shown in Fig. 2, E. This gonad is in a mature condition, for mature ova are found in the medullary portion of the ovotestis near the beginning of the gonoduct instead of in the cortical region where ovocytes of various stages of development are seen. Empty spaces are left in the gonad apparently by the spermatozoa which have vacated the FIG. 2. Drawings of different types of gonads of Limacina retroversa. A. Section of a complete gonad which is sexually undifferentiated. B. A " pure male " gonad in which no ovocytes are seen—section of a complete gonad. C . A hermaphroditic male gonad which has more than 75 per cent of its tissues made of male germ cells. Only the first or largest whorl is shown, the other two whorls being indicated by outlines. D. First or largest whorl of a hermaphroditic male gonad with 50-75 p
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
