. Chordate anatomy. Chordata; Anatomy, Comparative. BALANOGLOSSUS. MOUTH gills PiG_ 3_—Balanoglossus, a typical genus of the sub-phylum Hemichorda. (Redrawn after Bateson.) The pharynx is divided into a dorsal portion which contains the numer- ous gill-apertures and a ventral portion which functions as the digestive passage of the pharynx. Posterior to the pharynx, the body contains a series of gonadic sacs, each of which has a pore-like opening to the exterior. The sexes are separate. In the so-called liver region, the intestine shows a series of paired diverticula, each of which produces a c
. Chordate anatomy. Chordata; Anatomy, Comparative. BALANOGLOSSUS. MOUTH gills PiG_ 3_—Balanoglossus, a typical genus of the sub-phylum Hemichorda. (Redrawn after Bateson.) The pharynx is divided into a dorsal portion which contains the numer- ous gill-apertures and a ventral portion which functions as the digestive passage of the pharynx. Posterior to the pharynx, the body contains a series of gonadic sacs, each of which has a pore-like opening to the exterior. The sexes are separate. In the so-called liver region, the intestine shows a series of paired diverticula, each of which produces a corresponding bulging of the rela-. LONG bUSCLE OF PROBOSCIS BLOOD VESSEL Fig. 4.—Balanoglossus, the typical genus of the hemichordates, seen in left lateral aspect. The possession of both dorsal and ventral nerve-cords links hemichordates on the one hand with invertebrates and on the other with vertebrates. (Redrawn after Stempell.) For the purposes of the diagram, the body of the animal is bent upon itself. tively thin body-wall. These diverticula are glandular and supposed to have a digestive function, hence their name. Behind the liver-region, the intestine passes without convolution directly to the posteriorly situated anus. The circulatory system resembles that of annelids, but is supplemented by a lacunar system of lymph spaces. The nervous system consists of dorsal and ventral nerve strands containing occasional giant nerve cells. There are no special sense 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 Neal, Herbert V. (Herbert Vincent), 1869-1940; Rand, Herbert W. (Herbert Wilbur), 1872-1960. Philadelphia : P. Blakiston's Son & Co.
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