. A text-book of invertebrate morphology. Invertebrates. 442 INVERTEBRATE MORPROLOQY. abdomen. The seven anterior segments (the praeabdomen) of the abdomen are broader and thicker than the remaining five segments (the postabdomen), the last one of which ter- minates in a curved stout spine which bears at its extremity the openings of two ducts leading from a pair of glands lying in the twelfth abdominal segment and secreting a poisonous fluid. The chelicersB (cA) are small chelate appendages situated in front of the mouth, while the pedipalps (^"pe) are long and provided with atrong chela
. A text-book of invertebrate morphology. Invertebrates. 442 INVERTEBRATE MORPROLOQY. abdomen. The seven anterior segments (the praeabdomen) of the abdomen are broader and thicker than the remaining five segments (the postabdomen), the last one of which ter- minates in a curved stout spine which bears at its extremity the openings of two ducts leading from a pair of glands lying in the twelfth abdominal segment and secreting a poisonous fluid. The chelicersB (cA) are small chelate appendages situated in front of the mouth, while the pedipalps (^"pe) are long and provided with atrong chelae, their basal joints and those of the two succeeding appendages surround- ing the mouth and serving as jaws. The four pairs of appendages be- hind the pedipalps are all similar in form, being six-jointed walking- limbs. Upon the abdomen modi- fied appendages are also found, the second abdominal segment bearing a pair, each member of which consists of a single joint whose posterior edge is beset with a number of processes which give it the appearance of a comb, whence the name pectines iff) applied to these appendages. In front of the pectines lies the geni- tal opening, protected by a small genital operculum {op) which may possibly represent another pair of appendages belonging to the first abdominal segment. Upon the ventral surfaces of third, fourth, fifth, and sixth abdominal segments elongated pores are to be found which are stigmata (sf"') leading into the respiratory cavities containing the lung-books, of which there are in all four pairs in this group. No trachese occur. The intestine is quite straight in the Scorpions and lacks csecal outgrowths excepting the two Malpighian tubules sit-. FiG. 301.—Scorpion (after Owen), c/j = cbelicerse. O'p = genital operculum. pe = pedipalp. pi = pecten. si'-* = Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of th
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