. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 2 FIGURE 1. Microphotograph, haemal sinus from a specimen of N. trivittaius, with immature rediae and cercariae. FIGURE 2. Microphotograph, intense infection of Plenrobraclna f>ilcns exposed two hours to cercariae from N. trirattatus. levels in the water. In swimming, the body is contracted, bent ventrally, the tail is extended and lashes so fast that only a blur appears. They tend toward the light side of the container. They swim with the tail in advance and when contact with a medusa or ctenophore is made, the tail adhe
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 2 FIGURE 1. Microphotograph, haemal sinus from a specimen of N. trivittaius, with immature rediae and cercariae. FIGURE 2. Microphotograph, intense infection of Plenrobraclna f>ilcns exposed two hours to cercariae from N. trirattatus. levels in the water. In swimming, the body is contracted, bent ventrally, the tail is extended and lashes so fast that only a blur appears. They tend toward the light side of the container. They swim with the tail in advance and when contact with a medusa or ctenophore is made, the tail adheres and the cercaria turns to bring the anterior end of the body in position for attachment. By movements of the tail and body, the body penetrates the jelly and the contents of the penetration glands are extruded. When the body is firmly embedded, the activity of the tail frees it from the body and it swims away. When a specimen of Bcroe cucumis was placed in a bowl with swimming cercariae, they entered the grooves beside the comb-rows, penetrated, and migrated in the jelly. They did not penetrate the pigmented areas between rows. As the cercariae age, they move lower in the water and eventually sink to the bottom. The snail collected at Quissett on 20 July 1978 was shedding and continued to liberate cercariae every day until it was killed on 2 September to get the rediae and developing cercariae, (Figure 1). The snail taken 7 June 1979 was shedding and it continued until 20 July, after which no more cercariae appeared, although it was kept in cool running water and fed daily. It was crushed and examined on 17 August 1979 and contained about sixty rediae but no cercariae, either in the haemocoele or in the rediae. The liver was moribund, lacking in firm consistency and typical cellular organiza- tion, and the rediae contained only germ balls. It is well known that when a host is not properly nourished, trematode reproduction is retarded or ceases, and remains dormant until the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
