1. The reproductive function is not active in all fish at the same time or the same manner, nor are they pregnant during the same length of time. Before the season of sexual intercourse the males and females begin to assemble, and at the period of intercourse and the production of their ova they pair together. Some of them do not remain pregnant more than thirty days, and others not so long; but all of them remain so for a number of days, which can be distributed into seven. Those which some persons call marini remain pregnant for the longest period. The sargus becomes pregnant in the month of December, and remains so for thirty days. The kind of cestreus which some persons call the chelon and the myxon are pregnant at the same time as the sargus. All these suffer in their pregnancy, wherefore they are driven to the shore at this season; for in the vehemence of their desire they are carried towards the land, and always continue in motion during this period till they have produced their ova. The cestreus is more remarkable for this than any other fish. As soon as they have deposited their ova, they become quiet. 2. In many fish there is a limit to their reproductive powers, when worms make their appearance in their abdomen. These worms are small living creatures, which expel the reproductive substance. The small fry of the rhyas makes its appearance in the spring, and that of many others about the vernal equinox. Other fish do not produce at this season of the year, but in the summer or near the autumnal equinox. 3. The atherina produces its young first of all, near the land. The cephalus is the last. This is evident from the small fry of the former appearing first, and that of the latter last of all. The cestreus also produces among the first. The salpa in most places deposits its ova during the summer, and sometimes in the autumn. The aulopias, which they call anthias, produces its ova in the summer season. After these the chrysophrys, labrax, mormyrus, and all those which are called dromades; the trigla and cocarinus are the latest of all the gregarious fish. These oviposit in the autumn. The trigla deposits her ova in the mud, which causes her to be late, for the mud continues cold for a long while. The coracimus is next to the trigla, and goes among the sea weed to deposit her ova: consequently they frequent rocky places. It continues pregnant for a long while. The mænides oviposit at the winter solstice. Many other marine fish oviposit in the summer, for they are not captured at this period. The mænis is the most productive of all fish, and the batrachus the most so among the selache. They are, however, rare, for they perish very readily; they oviposit in shoals and near the land.