. Annual report of the Regents. New York State Museum; Science. Genera of the ISTorth American Palaeozoic Bryozoa. 453 ingly thin transparent membrane, a prolongation of the outer margin of the lophophore, fig. 22,5, which is known as the calyx. The calyx never exists in forms destitute of an epistome. Perigastric Space. The perigastric space is filled with a colorless fluid, which prob- ably fulfils the triple purpose of circulation, nutrition and respira- tion ; the last-named office probably in conjunction with the ten- tacles, but there is no absolute certainty on this point. The fluid is
. Annual report of the Regents. New York State Museum; Science. Genera of the ISTorth American Palaeozoic Bryozoa. 453 ingly thin transparent membrane, a prolongation of the outer margin of the lophophore, fig. 22,5, which is known as the calyx. The calyx never exists in forms destitute of an epistome. Perigastric Space. The perigastric space is filled with a colorless fluid, which prob- ably fulfils the triple purpose of circulation, nutrition and respira- tion ; the last-named office probably in conjunction with the ten- tacles, but there is no absolute certainty on this point. The fluid is colorless and the circulation, which undoubtedly takes place, is de- tected only through the medium of certain small particles, held in suspension in the fluid; but these particles are not necessary for. Fig. 23. Tentacle enlarged, showing outer cellular and inner membranous layer, the performance of the functions of the fluid, because they are fre- quently absent, and Mr. Hancock thinks that when they are present, it is from some rupture of the walls. Dr. Farre has described and figured parasites occurring in this fluid, but judg- ing from his figure, he mistook the spermatozoa for parasites, and he describes them as moving with a slow, undulating motion, which is characteristic of the spermatozoa. Allman is of the opinion that the perigastric fluid is chiefly aqueous and supplied from without In that case there must exist pores through the ectocyst capable of being opened and closed at the will of the animal or the water must exude through the alimentary canal. What the other constituents of this fluid may be has not yet been ascertained. Allman says : "That the fluid thus contained in the perigastric space and thence admitted into. 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 New York State Museum
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