. Protozoo?logy. Protozoa; Protozoa, Pathogenic. FERTILIZATION BY EXOGAMY 159 but not as complete as in the gregarines; one case, Adelea ovata, is interesting in that one of tlie conjugants is a large form similar to the ordinary vegetative individuals, while the other is much smaller and is derived from an individual which forms four gametes while attached to the other cell, one of these gametes penetrating the larger cell, while the other three degenerate and disappear. In this form also we have Fio. 69. Different forms of gametes in gregarines and coccidiidia. (After Shellack.) A, Stylo- rh
. Protozoo?logy. Protozoa; Protozoa, Pathogenic. FERTILIZATION BY EXOGAMY 159 but not as complete as in the gregarines; one case, Adelea ovata, is interesting in that one of tlie conjugants is a large form similar to the ordinary vegetative individuals, while the other is much smaller and is derived from an individual which forms four gametes while attached to the other cell, one of these gametes penetrating the larger cell, while the other three degenerate and disappear. In this form also we have Fio. 69. Different forms of gametes in gregarines and coccidiidia. (After Shellack.) A, Stylo- rhynclius longicoHis (after Leger); B, a sisecies of monocystis from Lumbricus (Cuenot); C\ spermatozoid of Echinomera hispida, to the left the two gametes of Pterocephalus nobilis; Z>, the two gametes of Urospora lagidis (Brasil); E, the same of Gregarina ovata (after Schnitzler): F, the same of Schaudinnella lienlete (after Nusbaum); G, the same of Cocci- dium schubergi (after Schaudinn). what may be regarded as complete sex differentiation, since the proto- plasm of the race forms individuals of male or female character, never both. Schaudinn and others have shown that the difference between the two conjugating forms is present in potential throughout the entire series of forms, the first division of the fertilized egg giving rise to individuals which can be identified as male or female. In this 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 Calkins, Gary N. (Gary Nathan), b. 1869. New York and Philadelphia, Lea & Febiger
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