. The elasmobranch fishes . Fig. 270. Diagram to sliow the hymen between oviduct and cloaca. (From Widako- wich.) cZ.,cloaca; 7ii/.,hymen; , oviduct; s., uterine septum. Barring the fact that the female may be slightly larger than the male, the most important second- ary character separating the sexes in the Elasmo- branchs is the presence of claspers in the male. These, as we have seen, are formed as modifica- tions of the inner lobe of the pelvic fin. In types like Heptanchus maculatus the claspers in immature specimens are relatively insignificant so that it is often difficult upon casu
. The elasmobranch fishes . Fig. 270. Diagram to sliow the hymen between oviduct and cloaca. (From Widako- wich.) cZ.,cloaca; 7ii/.,hymen; , oviduct; s., uterine septum. Barring the fact that the female may be slightly larger than the male, the most important second- ary character separating the sexes in the Elasmo- branchs is the presence of claspers in the male. These, as we have seen, are formed as modifica- tions of the inner lobe of the pelvic fin. In types like Heptanchus maculatus the claspers in immature specimens are relatively insignificant so that it is often difficult upon casual examination to distinguish male from female. In most other types, however, the claspers are well developed and in the rays they may be of enormous size. In one immature specimen of Heptanchus supposed to be a male, in addition to the rudimentary oviduct only one of the pelvic fins bore a clasper. The con- dition of gynandromorphism, in which one side of the body is male, the other female, has been found in insects and birds, and its occurrence in the Elasmo- branchs has also been previously noted (Vayssiere and Quintaret, 1915). The mucous covering of the claspers is usually devoid of placoid scales and is provided with a lubricant. Distally, as we have seen in a study of the skele- ton, the claspers are provided with one or more terminal pieces. These by muscular action may be erected at right angles to the main axis of the clasper. The claspers have long been known to function in uniting the male and female in copulation. This process among the Selachians was early studied byAgassiz (1871) who discovered that one (or both) of the claspers is inserted
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