Cothurnia imberbis Ehrenberg, var. curvula Entz. Fig. 63.

Synonyms: C. imberbis Kent et al.; C. curvula Entz; C. socialis Gruber?

The lorica is swollen posteriorly, narrowest at the oral margin, bent on its axis and is supported on a short stalk. It is perfectly smooth and without annulations. The animal itself has no definite stalk. When fully expanded the animal emerges but slightly from the margin of the cup. Fresh and salt water. On red algæ. Dimensions of Woods Hole form: Cup 50 to 55µ long; greatest diameter 22µ; length of stalk 4 to 5µ.

Fig. 63.—Cothurnia imberbis.
[ ENLARGE ]

Cothurnia nodosa Claparède & Lachmann. Fig. 64.

A. Smooth cup.—Cothurnia maritima Ehr., Eichwald, Stein, Kent.
B. Cross-ringed cup.—C. pupa Eichwald, Stein, Cohn; C. nodosa Cl & L.; V. crystallina Entz '78; C. pontica Meresch., Kent; C. cohnii and pupa Kent; C. longipes Kellicott '94.

The cup is elongated, swollen centrally, tapering at oral end and conical at base or rounded. Oral opening either circular or elliptical. Cross rings may or may not be present, and the cup is either smooth or annulate. Length of cup 70µ to 80µ. The stalk which supports the cup is extremely variable in length. The animal is borne upon a stalk of variable length within the cup.

Entz states that the many variations which this species exhibits run into each other so gradually that he does not believe it wise to separate them. The Woods Hole forms which I found on algæ of various kinds were nearly of a size, and did not vary much from the one figured. Kellicott '94 described a Cothurnia from Woods Hole under the name of C. longipes, which I believe is only a long-stemmed variety of C. nodosa. My form has the following dimensions: Cup 75µ; cup stalk 38µ; animal stalk 14µ.

Fig. 64.—Cothurnia nodosa.
[ ENLARGE ]