. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NEW SPECIES OF NEMERTEAN. 123 Cl ~dv ventral ly in the brain region to be again separated after a short space. At the posterior end of the brain region they are again united by a broad median lacuna which gives rise to the proboscis sheath vessel posteriorly (Fig. 4). Behind the mouth the lat- eral lacunae send off a great many an- astomosing blood spaces beside and be- neath the esophagus. On the walls of these blood spaces delicate branches of the nephridial tnlntlcs ramify in all direc- tions. From the pair of nephridial
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NEW SPECIES OF NEMERTEAN. 123 Cl ~dv ventral ly in the brain region to be again separated after a short space. At the posterior end of the brain region they are again united by a broad median lacuna which gives rise to the proboscis sheath vessel posteriorly (Fig. 4). Behind the mouth the lat- eral lacunae send off a great many an- astomosing blood spaces beside and be- neath the esophagus. On the walls of these blood spaces delicate branches of the nephridial tnlntlcs ramify in all direc- tions. From the pair of nephridial canals which lie on the lateral walls of the lateral blood spaces numerous efferent ducts pass through the muscular layers to the dorso-lateral aspects of the body as usual. These ducts are probably vari- able in number for in the single specimen sectioned there were thirteen on one side and only seven on the other. In addition to the seven ducts of this side were two incomplete or rudimentary ducts (Fig. 4, ed] which did not connect with the FIG. 4. Diagram of blood vascular system and nephridia. The two cephalic lacunas (<:/) unite an- teriorly by a rather broad anastomosis. In the brain region are two other anastomoses of the cephalic lacunae, from the posterior of which the dorsal vessel (dv] and the lateral vessels (fa) originate. The lateral vessels give rise to profusely branched anastomosing lacunae (,?/) beside and beneath the esophagus. Dor- sal vessel leaves the wall of proboscis sheath in the midst of nephridial region (.r). The nephridia (nep} lie on the lateral walls of lateral vessels about hal way between mouth and intestinal region, and send numerous branches among the esophagal lacunae. They open to exterior through numerous efferent ducts (eel ) on each side. In this specimen there were thirteen on one side and seven on the other. There are, however, two rudimentary ducts («/') on the side with the smaller number. nephridial canals at all and are apparent
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
