MARINE PROTOZOA FROM WOODS HOLE. 
439 
and is not sharply marked from the rest of the body hut tapers gradually, its base being equal to the 
diameter of the body at its middle point. The body is slightly contractile and the posterior end is 
carried to a rounded point, but not into a distinct tail. Unlike the fresh-water variety, this one has 
no hyaline margin nor hyaline caudal region, and the contractile vacuole is double or multiple on the 
dorsal side near the posterior end. Cilia are present only on the under (right) side, with, however, 
a row of large cilia marking the course of the elongate mouth, upon its left side. The right side is 
striated, the left arched and without markings. The endoplasm is finely granular with, however, 
larger food particles in the process of digestion, while specimens are occasionally seen with the natural 
form completely lost through distortion caused by over-large captures (Cf. also Wrzesniowski ’70, 
p. xxin, lig. 32). Movement continuous, slow, and gliding; very little tendency to jerking movements. 
Macronucleus double, both parts spherical, and placed in about the center of the larger part of the 
body; closely approximated but not, as Schewiakoff described, connected. In conjugation, a large 
form unites with a smaller one, the mouth parts being connected. Details of conjugation and macro- 
nuclei not made out. Length 200// to 600//. 
Key to marine genera of Chlamydodontidse. 
Diagnostic characters: Form usually ellipsoid, never very elongate. Transverse section of body circular or elliptical. 
The mouth is usually some distance from the anterior end and may be in the posterior part. Sometimes it is in the center 
of the ventral surface, again on the right side. The oesophagus invariably has a well-developed buccal armature, or a 
smooth peculiarly built oesophageal tube. Food particles of large size. 
1. Body cylindrical. Cilia about entire body Genus * Nassula p. 440 
Body flat 2 
2. a. Without a caudal process 3 
b. With a caudal process 5 
3. a. Anterior end angular on leftside 4 
b. Anterior end rounded Genus Chlamydodon 
4. a. Dorsal strise and cilia present, ventral cilia longer Genus Orthodon 
b. Dorsal strise and cilia absent; posterior end not pointed Genus * Chilodon, p 440 
c. Dorsal strise and cilia absent; posterior end pointed Genus Scaphidiodon 
5. a. Caudal spine with posterior bristle-like cilia 6 
b. Caudal spine without posterior bristle-like cilia, ventral cilia reduced Genus TrocliUia 
6. a. With pigment spot on anterior angle Genus JEgyria 
b. Without such pigment spot Genus Onychodactylus 
c. Cilia on right edge only of greatly reduced ventral surface Genus * Dysteria, p. 441 
