zhong hua jia xia de you ti xing tai
Author(s): WANG RONG
Pages: 35-58
Year: 1965 Issue: 1
Journal: Oceanologia et Limnologia Sinica
Keyword: 胸肢; 腹肢; 蚤状幼体; 无刚毛; 外肢; 发育期; 内肢; 基肢; 尾节; 第二触角;
Abstract: The material on which the present work is based was collected from the East China Sea and the Yellow Sea during the years 1958-1960. The developmental stages are determined by comparison of the morphological characters of its larval forms found in plankton samples and by analysis of its length frequency distribution. In this paper, the terms Protozoea, Zoea and Post-larva used in decapod nomenclature are employed instead of the old names Calyptopis, Furcilia and Cyrtopia of Sars.The main results obtained are as follows:1. The fertilized eggs are deposited in two ovisacs and are developed there until hatching. The number of eggs contained in the ovisacs is proportional to the size of the female (see Table 1).2. Nauplius stages are passed within the egg membrane. The larva dissected from the egg just before hatching is a typical Metanauplius. Freeswimming Metanauplii, however, were rarely found in the plankton sample. This may indicate that the Metanauplius stage is very transitory in its larval history.3. Three different forms were found in Protozoea. Judging from their length frequency distribution (text-fig. 1), each of them represents an actual stage. The main characters of these stages are given below:First stage-Abdomen unsegmented. Telson with six terminal spines. Uropods not yet developed.Second stage-Abdomen with six segments, the seventh segment not yet separated from the sixth. Telson with seven terminal spines. The developing uropods can be seen within the integument.Third stage-Abdomen with seven distinct segments. Telson with seven terminal spines. Uropods present.4. Fourteen different forms of pleopod development were found in Zoea (see Table 2), of which 0, 3, 4, 3'2, 4'1, and 5' are dominant. According to Fraser's conception, the path of pleopod. development may be formulated asThe length frequency histogram (text-fig. 2) clearly shows that each step in the pleopod development represents one developmental stage.The change in number of the terminal spines on the telson also provides further evidence to illustrate that the four stages judged from the pleopod development are successive stages. In the individuals just before moulting the number of terminal spines in the following stage can be seen through the old integument (Pl. Ⅲ, fig. 3; PI. Ⅳ,fig. 1; Pl. Ⅳ, fig. 3).5. Judging from the data of frequency distribution, there may be four stages in Post-larva. The second pair of postero-lateral spines on the telson has disappeared in the second stage. In the fourth stage the pseudoexopod of the first maxilla is present, and the sixth thoracic leg is fully segmented. It must be emphasized that in this species the exopod of the first maxilla is present throughout its life and only the outermost, long seta, disappears immediately after the appearance of the pseudoexopod.
Pages: 35-58
Year: 1965 Issue: 1
Journal: Oceanologia et Limnologia Sinica
Keyword: 胸肢; 腹肢; 蚤状幼体; 无刚毛; 外肢; 发育期; 内肢; 基肢; 尾节; 第二触角;
Abstract: The material on which the present work is based was collected from the East China Sea and the Yellow Sea during the years 1958-1960. The developmental stages are determined by comparison of the morphological characters of its larval forms found in plankton samples and by analysis of its length frequency distribution. In this paper, the terms Protozoea, Zoea and Post-larva used in decapod nomenclature are employed instead of the old names Calyptopis, Furcilia and Cyrtopia of Sars.The main results obtained are as follows:1. The fertilized eggs are deposited in two ovisacs and are developed there until hatching. The number of eggs contained in the ovisacs is proportional to the size of the female (see Table 1).2. Nauplius stages are passed within the egg membrane. The larva dissected from the egg just before hatching is a typical Metanauplius. Freeswimming Metanauplii, however, were rarely found in the plankton sample. This may indicate that the Metanauplius stage is very transitory in its larval history.3. Three different forms were found in Protozoea. Judging from their length frequency distribution (text-fig. 1), each of them represents an actual stage. The main characters of these stages are given below:First stage-Abdomen unsegmented. Telson with six terminal spines. Uropods not yet developed.Second stage-Abdomen with six segments, the seventh segment not yet separated from the sixth. Telson with seven terminal spines. The developing uropods can be seen within the integument.Third stage-Abdomen with seven distinct segments. Telson with seven terminal spines. Uropods present.4. Fourteen different forms of pleopod development were found in Zoea (see Table 2), of which 0, 3, 4, 3'2, 4'1, and 5' are dominant. According to Fraser's conception, the path of pleopod. development may be formulated asThe length frequency histogram (text-fig. 2) clearly shows that each step in the pleopod development represents one developmental stage.The change in number of the terminal spines on the telson also provides further evidence to illustrate that the four stages judged from the pleopod development are successive stages. In the individuals just before moulting the number of terminal spines in the following stage can be seen through the old integument (Pl. Ⅲ, fig. 3; PI. Ⅳ,fig. 1; Pl. Ⅳ, fig. 3).5. Judging from the data of frequency distribution, there may be four stages in Post-larva. The second pair of postero-lateral spines on the telson has disappeared in the second stage. In the fourth stage the pseudoexopod of the first maxilla is present, and the sixth thoracic leg is fully segmented. It must be emphasized that in this species the exopod of the first maxilla is present throughout its life and only the outermost, long seta, disappears immediately after the appearance of the pseudoexopod.
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