. The British Tunicata; an unfinished monograph. Sea squirts; Tunicata. 20 BRITISH TTJNICATA. spirals composed of minute secondary vessels. Thus each spiral coil is set, as it were, in a square frame, and forms a slightly-conical eminence which projects a little into the branchial cavity. A few radiating vessels pass from the apex of each cone to the points where the transverse channels are intersected by the secon- dary rectilinear vessels. Thus there are usually four such radiating vessels to each coil. The longitudinal bars are rigid and cord-like; they project considerably from the surface
. The British Tunicata; an unfinished monograph. Sea squirts; Tunicata. 20 BRITISH TTJNICATA. spirals composed of minute secondary vessels. Thus each spiral coil is set, as it were, in a square frame, and forms a slightly-conical eminence which projects a little into the branchial cavity. A few radiating vessels pass from the apex of each cone to the points where the transverse channels are intersected by the secon- dary rectilinear vessels. Thus there are usually four such radiating vessels to each coil. The longitudinal bars are rigid and cord-like; they project considerably from the surface of the gill. The papillary membranes. FIG. 30.—Part of the branchial sac of Corolla parallelogram/ma. Much enlarged. are ample, extending from bar to bar, and have the free margin considerably thickened, as is the case in Axcidia scalra. In Corella, as in Ascidia, there are no branchial papillse properly so-called; but the thick- ened edge of the membrane projecting from the bars occasionally becomes assimilated to papillae. The oral lamina is replaced by a series of well- developed filamentous processes, wrhich are wide at the base and taper to fine points; they extend from the top of the branchial sac and terminate near its. 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 Alder, Joshua, 1792-1867; Hancock, Albany, 1806-1873; Hopkinson, John, 1844-1919; Norman, Alfred Merle, 1831-1918; Embleton, Dennis, 1810-1900. London, Printed for the Ray society
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Keywords: ., bookcentury1900, bookdecade1900, bookpubli, booksubjectseasquirts
