. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). , 418 IN VEHTEBUA TE MOHPUOLOO Y. autenuules are uuirumous auil, like the other limbs, but iudis- tiuctly jointed, the autenuules und uiundibles being, however, biruuioiiH und possessing strong setie at their bases which function as jaws, though both pairs of appendages are essen- tially locomotor. Judging from the appeudages, therefore, the Nauplius may be regarded as consisting of five segments, one corresponding to the prostomial lobe of Auuelids and contain- ing the
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). , 418 IN VEHTEBUA TE MOHPUOLOO Y. autenuules are uuirumous auil, like the other limbs, but iudis- tiuctly jointed, the autenuules und uiundibles being, however, biruuioiiH und possessing strong setie at their bases which function as jaws, though both pairs of appendages are essen- tially locomotor. Judging from the appeudages, therefore, the Nauplius may be regarded as consisting of five segments, one corresponding to the prostomial lobe of Auuelids and contain- ing the primitive cerebral gangliou (archicerebrum), one cor-. Fig. 191.—Nauplius of Cetochilm aeptentrionalia (atter QnoBBatt). responding to each pair of appeudages and one to the region of the body behind the mandibles. A Nauplius of this simple form may be regarde ,s typical and is that which is found in the majority of the C oda and in the Cirrhipedia as well as in some Branchiopoda {Astheria, JLrmnadia). In the Ostracoda the arrangement of the limbs and segments is the same, but the bivalved shell characteristic of the adult is already developed, giving the Nauplius an ap- pearance very different from that of the Copepoda. Not un- frequently, however, as for instance in Apits among the Branchiopoda, and Leptodora among the Cladocera (the re- maining Cladocera, so far as is known, leave the egg with the adult form), the Nauplius, though possessing only the three pairs of appendages, yet shows indications in the post-maudib- ular region of a varying number of additional segments, and to this form it is convenient to apply the name Metanauplius. As a rule in the Eutomostraca further development con- sists of a series of moults (ecdyses), an increase in the number of segments and appendages and modifications of the latter taking place at each ecdysis, until the adult form is attained. No special larval forms beyond the Nauplius are common to. Please note that these images are ex
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
