. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MYRIAPODA,. fat which surrounds it on all sides, are seen to be perforated at intervals jc- with numerous valvular ori- °' fices, through which the cir- culating fluid gains free admis- sion from the general cavity of the body, and by the un- dulatory contractions of the dorsal heart thus constructed is forced forward toward the head. Arrived in the neigh- bourhood of the oesophagus^ the dorsal heart is seen to give1 off several vessels, and ac- cording to the opinion of Mr. Newport and Mr. Lord,* there is reason to
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MYRIAPODA,. fat which surrounds it on all sides, are seen to be perforated at intervals jc- with numerous valvular ori- °' fices, through which the cir- culating fluid gains free admis- sion from the general cavity of the body, and by the un- dulatory contractions of the dorsal heart thus constructed is forced forward toward the head. Arrived in the neigh- bourhood of the oesophagus^ the dorsal heart is seen to give1 off several vessels, and ac- cording to the opinion of Mr. Newport and Mr. Lord,* there is reason to suppose that a vascular system more com- plete than has as yet been proved to exist in any of the true Insects may be pointed out in this region of the body. The dorsal vessel itself, when examined under a microscope, is distinctly muscular, being formed of circular flat bands that surround the cavity of the tube, so that doubtless the action of this heart, in the larger species at least, is suffi- ciently energetic. Foramina npugnatoria.—These are a series of orifices which in the Julidse are seen upon the lateral aspect of every segment of the body, and communicate with as many minute mem- branous sacculi placed within the body. These sacculi, both from their position and relations., forcibly remind us of the series of respiratory sacs met with in the Leech and other air- breathing Annelidans, but in Julus they are supposed to be merely organs of secretion from which some offensive fluid is poured for the protection of the animal. Nervous si/stem.—The nervous system of the Myriapoda, as in all the Articulata, exhibits a double series of ganglia connected by cords of inter-communication. The supra-cesophageal ganglion, situated within the cephalic segment of the body as relates to its development, seems to hold a place intermediate between that of the Annelida and of Insects, or perhaps more strictly speaking, corresponds with the larva condition of the latter. The vent
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