. Fresh-water biology. Freshwater biology. Caudal region not differentiated at all or only very poorly indi- cated. In general structure the Bothriocephalid larvae with two sucking grooves are like the true plerocercoids with 4 acetabula. Larvae prominently of Proteocephalidae, also of Cyclophyllidea from reptiles. One special form known as Gryporhynchus has been identified as the larva of Dilepis or some alhed genus. Fig. 763. Proteoce^Aa/Ms plerocercoid; a, from the body cavity; 5, from cyst, suckers drawn within body. Note large end Jrgan, shaded; c» from intestine; optical sections, X lo.
. Fresh-water biology. Freshwater biology. Caudal region not differentiated at all or only very poorly indi- cated. In general structure the Bothriocephalid larvae with two sucking grooves are like the true plerocercoids with 4 acetabula. Larvae prominently of Proteocephalidae, also of Cyclophyllidea from reptiles. One special form known as Gryporhynchus has been identified as the larva of Dilepis or some alhed genus. Fig. 763. Proteoce^Aa/Ms plerocercoid; a, from the body cavity; 5, from cyst, suckers drawn within body. Note large end Jrgan, shaded; c» from intestine; optical sections, X lo. (After La Rue.) 128 (127) Spaces in larva between folds of tissue, surrounded by cyst Scolex in natural position, . ... Cysticercoid.' Usually with caudal appendage in a posterior hollow of the cyst, and on the tail the embry- onic booklets of the onchosphere. In form and texture the cyst varies greatly. Calcareous bodies abundant, mostly on the invaginated layer between the cyst and the scolex which corre- sponds to the neck when the larval head is evaginated. Very frequent among Cyclophyllidea. Relationship between the cysticercoid and the adult may be inferred from careful examination of the scolex and its armature. No records exist of the presence in North Ameri- ca of these forms. For convenience in recogniz- ing them a figure is in- cluded of an abundant European form likely to occur here also in similar aquatic hosts. While these cysticercoids are most frequently recorded from Copepoda, Ostra- coda, and other small aquatic Crustacea, they occur also in Lumhricu- lus and other small an- nelids, and more rarely in small snails and slugs. Fig. 764. Drepanidotaenia fasciata. a, body of Cyclops agilis, containing larval tapeworm (cysticercoid); h, same larva with enormously long tail, isolated from the crustacean; c, cysticercoid with extended head, mag- uihed. (After Mr^ek.). Please note that these images are extracted from scanned page images that may have been digitally e
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
