MARINE PROTOZOA FROM WOODS HOLE. 
461 
So many species of Vorticella have been described that the task of collecting data and of arranging 
the synonyms is extremely irksome and difficult. Stokes enumerates 66 species, inhabiting fresh and 
salt water, and several other new species have been added since his work. I am impressed with the 
fact that new species have been created without proper regard for the manifold variations which 
nearly all of the Ciliata show, and I believe the 66 species might be safely reduced to 12 or 15. 
Vorticella patellina Muller. Fig. 59. 
Body campanulate, widest at anterior border, from which it tapers directly to the pedicle. The 
diameter of the peristome is a little larger than the length of the body. The ciliary disk is but little 
elevated. The cuticle is not striated and the body plasm is quite transparent. Length 52//. 
Vorticella marina Greeff. Fig. 60. 
The body is conical but variable, and may be short or elongate, so that relative length and breadth 
offer no chance of identification. In general the body is campanulate. The distinguishing feature 
is the transverse annulation of the bell. 
Small, but common, and grows in small social groups. Length 35/*. 
Fig. 62. — Cotliurnia crystalllna. 
Genus ZOOTHAMNIUM (Bory de St. Vincent 1824) Stein ’38, ’54* 
Colorless and highly contractile forms growing in small or large colonies. The form and structure 
of the individuals is not different from Vorticella. The colonies are usually richly branched upon the 
dichotomous plan and the entire colony is contractile. The main character is that with each division 
of the individual the stalk also divides, each daughter cell getting one-half of the parent stem. The 
stems therefore remain in communication, so that a simultaneous contraction results, and the colony 
as a whole is withdrawn. In some species so-called macrogonidia, or larger sexual individuals, are 
developed alongside the usual ones. Fresh and salt water. 
Zoothamnium elegans D’Udekem ’64?. Fig. 61. 
The bodies are variable — peristomial border widely dilated, tapering and attenuate posteriorly. 
The pedicle is slender, smooth, and transparent, and branches sparsely at its distal extremity. There 
are but few zooids (3 to 4) . , The ciliary disk projects conspicuously beyond the peristomial border. 
The pharyngeal cleft is very distinct and extends beyond center of body. Length of body 80// . 
Genus COTHURNIA (Ehr. ’31) Clap. & Lach. ’58. 
Colorless forms of medium size — in some cases they may lie green by Zoochlorella. The general 
structure is similar to that of Vorticella, but the individuals are elongate and occupy houses. The 
macronucleus is invariably long and band-form. The distinguishing character is the colorless or 
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