world of amoeboid organisms

Corntheca saccifera, from Wailes, 1913


Cornutheca saccifera Wailes, 1913

Diagnosis: Test of large size, pyriform, compressed, colorless, formed of circular o usually imbricated ; provided with two hollow curved horns, projecting internally, arising at each side of the test above the widest part, and communicating at the base with the exterior by a small slit-like orifice ; test in lateral view narrowly pyriform ; transverse section elliptical, prolonged at each end into a shallow keel ; aperture elliptical ; nucleus large, placed posteriorly, containing several nucleoli; plasma normal (original description).

Dimensions: Length 203-210 µm, breadth 126-145 µm; aperture 38-45 µm X 20-23 µm; thickness one half to two thirds of the breadth; length of horns 35-60 µm.

Ecology: Sphagnum. Lakehurst; Absecom (Leidy),N.J.; Good Ground, Long Island.

Remarks: Wailes, 1913: “Leidy found only two empty tests of this species, and he realized that although related to, they were distinct from Nebela equicalceus, from which species it is distinguished by the absence of the horseshoe-shaped keel around the fundus, by the horns not being solid, and the smaller size of the test with a shorter neck. The small openings at the base of the horns are very narrow slits usually indistinguishable but readily detected if a test be removed from water into oil of cloves, when the oil can be seen entering through them : although not uncommon in several gatherings and many living individuals -were seen, none were active. No specimens of N. equicalceus were found. It may perhaps be more than a coincidence that if the space occupied by the horns were vacant the test would then be similar to that of N. ansata, and the small discs often attached to the horns of that species (Leidy, Pl. 25. fig. 1) may represent the discarded material.”


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