A preliminary report on the Protozoa of the fresh waters of Connecticut / by Herbert William Conn.

  • Herbert William Conn
Date:
1905
Catalogue details

Licence: In copyright

Credit: A preliminary report on the Protozoa of the fresh waters of Connecticut / by Herbert William Conn. Source: Wellcome Collection.

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    Following the key I have given brief diagnostic descriptions of the determined genera. In these descriptions I have also followed the plan of Kirchner and Blochmann, in including only the essential characters, leaving out the subordinate de- tails which are liable to confuse the student rather than aid in identification. In the description of the genera only those are described in this preliminary report which have already been actually identified by myself, as occurring in our waters. There are doubtless other genera in Connecticut, which will be found later, and their descriptions will be given in subsequent reports. I have found several types of Protozoa existing in our waters, sometimes in considerable abundance, that do not agree with any described genera. Whether to regard these as new genera or modified forms of described genera I am as yet un- certain. In this preliminary report they are called new genera, and descriptions are then given. No attempt is made at present to give them names, for I regard it preferable to reserve the final descriptions and the naming of such types until a later report, when a longer period of study may enable me to de- termine more accurately whether these genera are connected by intermediate grades with any of the types already described^ or whether they should be regarded as really new. Descriptions of species are wholly omitted in this report The Protozoa are known to be widely variable, and it is, there- fore, always a matter of great difficulty to determine where to draw the limits between species. Two different attitudes toward this question may be adopted. One is to describe each distinguishable type as a separate species, and the other to group large numbers of closely allied forms together under the name of one species, even though they show wide varia- tions. The latter method appears to me, on the whole, pref- erable ; but if it is to be done, it can only be done after a long study of the different varieties that may be found, a study much more extended than it has been possible as yet to give to the subject. Moreover, the specific descriptions of Protozoa are so widely scattered in literature that it is a great task to obtain them all. Up to the present time I have not been able to search all this literature, in order to identify all the species
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