MARINE PROTOZOA FROM WOODS HOLE. 
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usually single, elliptical in form, and centrally placed; one micronucleus. Reddish granular pigment 
and trichocysts are occasionally present. 
Chilodon cucullulus Mull., sp. Fig. 35. 
Synonyms: Colpodci cucullus O. F. Muller; Loxodes cucullulus? Chilodon uncmatus Ehr. ’58, Perty ’52, Dujardin *41; 
L. dentcitus Duj., etc. 
This extremely variable form has received so many different names that it hardly pays to enum- 
erate them. It is one of the commonest and most widely spread eiliates known, although at Woods 
Hole I was surprised to see it so rarely. It is the type species of the genus and needs no further 
description. The specimens observed at Woods Hole had numerous contractile vacuoles and were 
42 to 45// long and from 28 to 32// wide. 
Genus DYSTERIA Huxley ’57. 
(Cl. et Lach. ’58; Entz '84; Mobius ’88; Shevyakov ’90.) 
Small forms, firm in outline, and colorless or slightly colored. The body is somewhat clam-shaped, 
flattened, slightly curved or straight on the right side, the other more convex. The true ventral side 
is only a narrow strip along the right and anterior edge of the body, the apparent ventral side being 
a fold of the very large dorsal surface which comes around ventrally, forming a valved structure some- 
what analogous to a clam shell. Cilia are limited to the outer edge of the small ventral surface, which 
also bears a peculiar spine at the posterior end. Behind this spine are larger cilia. The mouth 
opening lies in the anterior widened portion of the ventral surface and is connected with a smooth 
tubular pharynx. The right half of the dorsal side, i. e., the apparent dorsal side, is arched and bears 
longitudinal ridges. Two to four contractile vacuoles are placed on the ventral side. The macro- 
nucleus is usually dorsal, elliptical, and cleft., with one micronucleus attached. Fresh and salt water. 
Dysteria lanceolata Cl. et Lach. Fig. 36. 
Synonym: Cypridium lanceolatum Kent ’81. 
Outline of the flattened body ovoid; body consists of two valve-like portions; the edge of the 
right valve is nearly straight, that of the left valve more or less sinuous; anteriorly it is cut away, 
obliquely and posteriorly it has a deep indentation in which the seizing spine rests. The cilia are 
confined to the ventral surface, here reaching, however, from the anterior dorsal extremity to below 
the posterior indentation. Posteriorly the cilia become larger, corresponding to the larger cirri of 
D. armata, which are posterior to the spine. The mouth lies between the two valves and is surrounded 
by a long and smooth buccal armature which passes downward and backward to the left a distance 
equal to about half the entire body length. The macronucleus is situated in the dorsal region in the 
central part of the body. There are two contractile vacuoles, one behind the center of the buccal 
armature, the other near the inner end of this organ. Movement is in circles, the animal moving 
around quite rapidly when not attached by its posterior process. It is colorless and measures 45// in 
length by 27// in width. Claparede & Lachmann and Shevyakov describe it as 70// long. 
