. Elementary text-book of zoology. NEPHROPS. 219 of the mouth. The ganglia corresponding to them follow suit and fuse with the primary brain to form one mass. In a similar manner the ganglia of the next six append- ages, which are all jaws or foot-jaws, fuse to form one large sub-Ksophageal mass. After this follow the five thoracic ganglia of the chelae and the legs, and, lastly, the six abdo- minal ganglia. The last supplies both the sixth segment and the telson, and thus may be two (6th and 7th) fused ganglia. In this way the primitive chain of twenty ventral ganglia is reduced in number by
. Elementary text-book of zoology. NEPHROPS. 219 of the mouth. The ganglia corresponding to them follow suit and fuse with the primary brain to form one mass. In a similar manner the ganglia of the next six append- ages, which are all jaws or foot-jaws, fuse to form one large sub-Ksophageal mass. After this follow the five thoracic ganglia of the chelae and the legs, and, lastly, the six abdo- minal ganglia. The last supplies both the sixth segment and the telson, and thus may be two (6th and 7th) fused ganglia. In this way the primitive chain of twenty ventral ganglia is reduced in number by fusions at each end till twelve only remain. The lobster excretes nitrogenous waste products by a pair of green glands in the head, which may be a pair of much _ . modified nephridia. Each consists of a complex excretory tube leading to a bladder, which opens to the exterior by the excretory pore on the ventral side of Fig. 147.—Lateral View of Nephrops. (Adnat.) Scaphognathite. Pleurobranch. 3rd Maxillipede,. Chela ^ _ With branchial plate removed. Behind the scaphognathite are the epipodites of the first two foot-jaws, then follow the five podobranchs and their epipodites. The arthrobranchs and three of the pleurobranchs are hidden. the antenna. The excretory products are thus discharged into the stream of water emerging from the branchial chamber (see below). We may notice that the tubes have no internal nephrostome, for there is no coelomic body-cavity into which they can Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Masterman, Arthur Thomas. Edinburgh, E. & S. Livingstone
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