NOTES ON JAPANESE PROTOZOA

WITH FIGURES AND DESCRIPTIONS OF NEW AND RARE SPECIES

No. 2

C. H. EDMONDSON AND R. H. KINGMAN

The fresh-waters of Japan afford a wonderful opportunity for the enthusiastic microscopist. Conditions under which simple organisms thrive are not wanting anywhere in that country. Flooded rice fields of the lowlands, cool mountain streams and innumerable lakes, large and small, are teeming with low plant and animal forms. To what extent systematic study of the microscopic fauna and flora of the waters of Japan has progressed, under the direction of the eminent biologists of that country, the writers of this article are not able to state.

With a view of determining the species of Protozoa characteristic of Japan and comparing them with the American forms, microscopic studies were carried on by C. H. Edmondson during July and August, 1912, in various parts of the main island. Beginning with Kobe, observations were made through the central and eastern sections of the country and as far north as Lake Chuzenji.

Material was gathered from rice fields, small pools, streams and lakes. Collections were made from the following large lakes: Lake Biwi, altitude above sea level 328 ft.; Lake Hakone, altitude 2,378 ft.; Lake Chuzenji, altitude 4,375 ft. Since the survey covered a wide territory with considerable variation in local conditions as well as in altitude, the list of species embodied in this brief report may well represent the characteristic unicellular fauna of the entire country. The portion of this article concerned with Rhizopoda is largely a result of the work of R. H. Kingman, a student of zoology,

who identified and studied many forms from preserved material. By comparing the list which follows with numerous local records of observers in America and other parts of the world one sees some added evidence of the wide distribution of many species of Protozoa. The accompanying figures, prepared by Mr. Kingman from permanent mounts, represent new, or rare species of Rhibopods or forms showing considerable variation.

Phylum PROTOZOA: Subphylum SARCODINA:

Class RHIZOPODA

Amoeba Ehrenberg.

Subclass AMOEBEA

Order GYM NOMOEBIDA

Family Amoebidae

A. proteus Leidy; A. guttula Duj.; A. sphaeronucleus Greef; A. striata Penard; A. radiosa Ehr.; A. saphrina Penard.

The species of this genus were not common in any locality. Material from Myoho-in Temple grounds, Kyoto, furnished the best examples. Large individuals of A. radiosa were taken from Lake Hakone.

Hyalodiscus Hertwig and Lesser. H. rubicundus H. and L.

But one individual was observed. A very typical form, reddish-brown in color. From a rice field, Kyoto.

Arcella Ehrenberg. A. vulgaris Ehr.; A. discoides Ehr.; A. costata Ehr.; A. arenaria Greef.

Of the above species A. vulgaris is the more widely distributed in Japan. Lake Chuzenji and the region of Kyoto furnished the best material.

Centropyxis Stein. C. aculeata Stein.

Found in all localities. Very abundant in Lake Hakone. Great variation in size occurs in this species and some very large forms were observed.

Pixidicula Ehrenberg. P. cymbalum Penard.

A species rarely observed. Found in material from Lake Hakone.

Lecquereusia Schlumberger. L. spiralis Ehr.; L. modesta Rhumbler. These two speices are widely distributed in Japan, the former being much more abundant. In the typical L. spiralis the aperture

is usualy directed obliquely toward one side with a prominent hump at the outer base of the neck. In the common form in Japan the aperture is directed almost straight forward, in very rare cases there being a slight prominence at the base of the neck. Common in Lake Hakone. Typical examples of L. modesta were found in lakes on Mt. Rokkozan.

L. epistomium Penard, a common species of the high lakes of Colorado, was not observed in Japan. Difflugia Leclerc. D. pyriformis Perty; D. lobostoma Leidy; D. constricta Leidy; D. acuminata Ehr.; D. tuberculata Wallich; D. lebes Penard; D. bacillariarum Perty; D. elegans Penard.

Of the species of Difflugia in Japan, D. elegans is apparently the most common. It is widely distributed and shows a great range of variation. D. lebes, not uncommon in some of the lakes of Colorado, was observed but once, in material from the bottom of Lake Hakone.

Pontigulasia Rhumbler. P. spectabilis Penard.

But one individual observed. From Lake Hakone. A very typical form.

Quadrulella Cockerell. Q. symmetrica Schultze; Q. symmetrica var. curvata Wailes.

Very typical forms of the species were taken from shallow lakes on Mt. Rokkozan. The variety, observed but once, was found in Lake Hakone.

Nebela Leidy. N. collaris Leidy; N. crenulata Penard; N. hippocrepis Leidy; N. triangulata Lang.

In the material collected in Japan species of Nebela were very

rare.

There can be no reason to believe, however, that the genus is not well represented in that country. One individual of the rare species, N. hippocrepis, was found in material from Mt. Rokkozan. In the ooze from the rocks along the shore of Lake Hakone and from the border of a shallow lake on Mt. Rokkozan was found a species which is here listed under the name N. triangulata Lang.

The Japan species resembles, in some particulars, Nebela bipes Carter, as described in Clare Island Survey, Part 65, by Wailes

and Penard, and may represent an intermediate form between N. triangulata and N. bipes.

In the Japan form the shell is very transparent, compressed, irregular in outline with the fundus region inflated in an asymmetrical manner. The aperture is slightly oval.

Great variation exists in the form of the shell and in the arrangement of the plates. In some the plates are circular or oval, distinctly separated from each other with the ground substance of the shell intervening. In others the plates are closely crowded together and very irregular in outline, while in some the plates are regular in outline but distinctly overlap each other. The irregular inflation of the fundus is a characteristic feature. Usually the posterior lateral borders are expanded into lobes of variable size. In some these prolongations are pointed as in N. bipes, but more often they are blunt or rounded. Occasionally the fundus is truncated posteriorly, sometimes it is strongly concave. The extensions of the fundus are seldom uniform on the two sides of the shell and are never the same in two individuals. Usually the narrow view of the shell presents an irregular outline. The compression of the shell is seldom uniform, but is always stronger at the fundus border.

The size of the Japanese form ranges from 80 to 100μ in length, including the prolongations of the fundus; from 60 to 80μ in breadth of fundus and from 28 to 60μ in the long diameter of the aperture.

No living individuals were observed.

Heleopera Leidy. H. picta Leidy.

Material from Mt. Rokkozan furnished the only species of the genus observed. Under high power the plates are seen to be circular, slightly overlapping. Little foreign material is attached to the shell.

Phryganella Penard. P. hemisphaerica Penard.

Frequently observed in many localities.

Campascus Leidy. C. dentatus, sp. nov.

In 1877 Leidy discovered Campascus cornutus in China Lake, Wyoming, at an altitude of 10,000 feet. Apparently the species has not been observed since that time.

More recently Penard described two species of the genus, Campascus triqueter and Campascus minutus, from the deep lakes of Switzerland. In both species described by Penard the fundus is without the horn-like prolongations of the form observed by Leidy. Campascus minutus was reported by Wailes in 1912 from the New York water-supply drawn from Croton Lake Reservoir.

The form under consideration, which is apparently a new species, was found in the ooze taken from the rocks along the shore of Lake Hakone, Japan, in August, 1912.

The description follows: Shell of yellowish, chitinoid material similar in general outline to Campascus cornutus. Under high power the shell has the appearance of being distinctly punctate. In some individuals the punctae are arranged in a regular diagonal manner, in others there is no regularity about the arrangement. In no specimens examined can outlines of plates be detected even with the oil immersion lens.

The neck is short and sharply bent, nearly at right angles to the long axis of the shell. The circular aperture is bordered by a thin delicate membrane of approximately 4μ in breadth.

A number of short, blunt, tooth-like prolongations are present on the posterior border of the fundus. From three to seven of these processes are usually present. They vary in size and when numerous give an irregular, crenulated appearance to the posterior edge of the fundus, when the broad side of the shell is viewed.

In Leidy's species the two horns are directed laterally and posteriorly, their tips not projecting beyond the posterior border, giving the fundus a rounded outline when the narrow side of the shell is observed. In this species the teeth-like points are directed backward and project beyond the border, giving the fundus the appearance of terminating in a spine when the narrow side of the shell is seen.

Leidy records the size of Campascus cornutus as ranging from 0.112 mm. to 0.14 mm. long by 0.18 mm. broad.

This species of Japan is much smaller. The length of the shell, including the spines and the collar about the aperture, ranges from 60 to 80μ. Breadth of fundus from 50 to 66μ.