. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. ARACIINIDA. 207. \ Fig. 90. b be rectly termed the tail. In the Aran- a idee the ganglions are fewer than in the Scorpionidte: <* the first pair, or that which consti- d tutes the brain, (l/?,o,)isquite distinct from the thoracic; these are four in number (66) but have under- gone a remarkable degree of centrali- zation, being inti- mately connected together so as in- deed to form a mass in which all traces of junction are lost, except at s the sides, which have remained free and in the form of smallconoid bodies
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. ARACIINIDA. 207. \ Fig. 90. b be rectly termed the tail. In the Aran- a idee the ganglions are fewer than in the Scorpionidte: <* the first pair, or that which consti- d tutes the brain, (l/?,o,)isquite distinct from the thoracic; these are four in number (66) but have under- gone a remarkable degree of centrali- zation, being inti- mately connected together so as in- deed to form a mass in which all traces of junction are lost, except at s the sides, which have remained free and in the form of smallconoid bodies directed outwardly so as to resemble, in the aggregate, the figure of a star. From the apex of each of these small cones the nerve is given off to each leg. In the abdo- men there does not exist any ganglion, but only a double longitudinal ner- vous cord(c),which swells out at its ter- mination. From this swelling (rf) a great number of nerves (ee) pass off, which are distri- buted to all the organs contained in the abdominal cavity. Organs of sense. —We have no- thing particular to observe with re- spect to the smell or hearing of the arachnidans, for we are ignorant of the existence of these senses in the class, or at least of the parts of the body in which they are seated. With re- gard to taste, the choice which the arachnidans make of their food sufficiently indicates that it exists in variable degree ; the organ is situated probably at the entrance of the pharynx. With regard to touch, the delicacy of that sense is in the ratio of the tenuity of the integument; but the extremities of the legs, and more especially of the maxillary palps seem to be expressly destined to bring the individual Fig. 91. \. 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 Todd, Robert Bentley, 1809-1860. London, Sherwood, G
Size: 949px × 2634px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, booksubjectanatomy, booksubjectphysiology, booksubjectzoology
