. A monograph of the Najades of Pennsylvania . farther back, the two outer canals (belonging to the outer gills) open into and unite with this cloacal In a posterior view (See fig. 4) the diaphragm separatingthe branchial and cloacal openings forms a rather short, sim-ple, horizontal bridge, from which the gills hang there is a slight median incision, when the two in-ner laminae of the inner gills are not fully united to theirends, but according to my investigations this has no system-atic value. We are to note an exception to the normal structure, andthis is again Mar
. A monograph of the Najades of Pennsylvania . farther back, the two outer canals (belonging to the outer gills) open into and unite with this cloacal In a posterior view (See fig. 4) the diaphragm separatingthe branchial and cloacal openings forms a rather short, sim-ple, horizontal bridge, from which the gills hang there is a slight median incision, when the two in-ner laminae of the inner gills are not fully united to theirends, but according to my investigations this has no system-atic value. We are to note an exception to the normal structure, andthis is again Margaritana margaritifera. Here (See fig. 6) thediaphragm represents an entirely different aspect, which isdue to the fact that, as we have seen above, the outer lam-inae of the outer gills are not connected with the mantle up totheir ends. Thus on the one hand the outer attachment ofthe diaphragm is not seen at the outer edge of the mantle, and the outer laminaeof the outer gills are free for a considerable distance, which causes the whole dia-. Fiu. 4. Anodonia grandit giyantea (Lea). Posteriorview, showing branchial,anal, and supra-anal open-ings, diaphragm, and pos-terior ends of gills.
Size: 1340px × 1864px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1910, bookyear1911
