The endopodite is slender. The cardiac stomach opens into the py­loric stomach through a narrow X-shaped cardio-pyloric opening, guarded by an anterior, one posterior and two lateral valves. Planktonic, coxa of trunk appendages provided with gills (Order Diplostraca, Anostraca) Order Diplostraca. The appendages are two pairs of anten­nae, one pair of jaws, two pairs of max­illae, three pairs of maxillipeds and five pairs of pereopods or walking legs. (Fig. A biramous appendage is one that has two branches. 25.11). The gill is attached to the body about the middle of its length, and is highly vascular. The antennules (or first antennae) are generally regarded as true appendages, although they differ from all the other appendages in the facts that they are always innervated from the "brain" (or preoral ganglia) and that they are uniramous in the earliest and in the adults of all sub-classes except the Malacostraca, where they are biramous or sometimes triramous. Respiratory System 6. 4. Each ommatidium is separated from its neighbours by a partition of pigment cells, the chromatophores. It runs obliquely to the ventral region of the body either through the right or left side of the midgut. It is lodged in a special haemocoel, the pericar­dial cavity, the walls of which form the pericardium. A two-jointed shaft, proximally at­tached to the integument by a flexible mem­brane. Endopod: Mesial ramus of a biramous appendage, especially one arising from the basis or from the protopodite of the pleopod. The decapod abdomen normally bears six pairs of biramous appendages, which are used in swimming in many shrimps and prawns, while in the crabs and crayfish the first two pairs in the male are modified to help in sperm transfer during mating. 60+ What is the hard dorsal shield known as in crustaceans? The portion of the carapace covering the gills are called branchiostegite or gill cover. In the male the genital opening is present on the arthrodial membrane between the thorax and 5th walking leg. It then pierces through the thoracic ganglionic mass of the ventral nerve cord and divides into two branches. The basal part of coxa is divided into two parts, it shows a mandibular and incisor process. At daytime, when the intensity of light is high, the vision is of mosaic type. A median cardio pyloric strand and 2 lateral strands support the heart in the pericar­dium. An elongated lateral groove is present on either side of the plate. Many of the common insects we encounter on a daily basis—including ants, cockroaches, butterflies, and flies—are examples of Hexapoda. The gill-plates are larger in size in the middle but smaller towards the ends. The anus opens on the ventral side near the base of the telson. The last pair of abdominal limbs is frequently different from the others and is called the uropod s. a. The female reproductive system con­sist of a pair of ovaries, a pair of oviducts and a pair of female gonopores (Fig 25.15B). They are called Gnathobases. The heart (Fig. The body is distinctly divided into two parts— cephalothorax and abdomen. The 3rd. The first two pairs are chelate. In prawn, two types of visions are found. Arising from the posterior end of the pyloric stomach it runs backward, ascending between the two lobes of the hepatopancreas to reach the dorsal groove in the abdomen beyond cepha­lothorax and runs posteriorly to end in the rectum in the last segment. A horizontal pericardial sep­tum forms the floor of the pericardial sinus. 25.14C) consists of: 1. Maxillipeds, maxillulae and maxillae help in tearing it into pieces. Project Name: e-Content for zoology experiments Project Investigator: Dr. Nikunj Bhatt Module Name: Prawn: appendages Cephalic Appendages (Fig. The pleopods act like oars. Respiration: through the gills or general body surface. 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