. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SALT GLAND OF THE GULL 163 Gross anatomy In the gull the large, paired salt gland is situated on the top of the skull in the supraorbital grooves of the frontal bone (Fig. 1). Strictly speaking each gland consists of two parts, as seen from the fact that there are two ducts on each side of the head leading forwards into the beak (Technau, 1936). However, the two parts of the gland have a similar structure and are joined so closely together that they can be considered as one functional unit and may be regarded as one gland. T
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SALT GLAND OF THE GULL 163 Gross anatomy In the gull the large, paired salt gland is situated on the top of the skull in the supraorbital grooves of the frontal bone (Fig. 1). Strictly speaking each gland consists of two parts, as seen from the fact that there are two ducts on each side of the head leading forwards into the beak (Technau, 1936). However, the two parts of the gland have a similar structure and are joined so closely together that they can be considered as one functional unit and may be regarded as one gland. Thus, the glands are flat and crescent shaped, and two ducts pass from the anterior end of each to the anterior nasal cavity (vestibulum). On the upper side the gland is covered by a thin, tough connective tissue membrane. The anterior part of it extends somewhat laterally from the margin of the frontal bone and forms part of the roof of the orbit. Blood vessels and nerves pass from the orbit into the gland through holes in the frontal FIGURE 1. Skull of the herring gull from above, showing the position of the salt gland. The two ducts on each side of the head take their origin from the lower side of the anterior part of the gland and run close together into the beak, where they open at the posterior end of the vestibular concha (Marples, 1932; Technau 1936). The lateral duct opens on the lower median side of the vestibular concha (pre-concha) while the median duct has its opening on the nasal septum close to the transverse fold separating the anterior nasal cavity (vestibulum) from the upper nasal cavity. The openings of the ducts can be found if a longitudinal incision is made in the palate somewhat lateral to the midline, and it is then pos- sible to cannulate the lateral duct opening for the collection of secretion in living birds (Fange, Schmidt-Nielsen and Robinson, 1958), or for injection of fluids into the duct. For some reason our attempts to cannulate the median
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
