北海道に Pheretima communissima (Goto et Hatai) が産すること
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(2) Vol. 12, No. 1 I[B Journal of Hokkaido Gakugei University Aug., 1961. Occurrence of Pheretima communissima. (Goto et Hatai) in Kokkaido Tokukichi Takahashi Fukushima primary school, Fukushima, Oshima and. Hideji Yamaguchi Biological Laboratory, Hakodate Branch, Hokkaido Gakugei University. fKWfS^ • lllR^zl : ^t^TH^ Pheretima communissima (Goto et Hatai) ^ilg't'% C. ,h (With one Text-fugure) The present species is one of well-known earthworms in Japan, having a wide. distribution in Honshu. According to Kobayashi (1941) it is distributed in Chugoku, Kinki, Chubu, Kanto and Tohoku territories. On the other hand, Ohfuchi (1947) has noted that it is commonly found in Japan, but its northern occurrence may be limited to Iwate Prefecture. Then it has been generally supposed that the present species is not found in Hokkaido. However, many specimens identical with the species have been recently found by the present writers in a collection of terrestrial oligochaetes from the southern part of Hokkaido. Our findings on them are as follows. Material : 8 clitellate specimens collected in a cultivated field at Hachiman-cho in Hakodate in Aug. 1956 ; 19 clitellate ones from cultivated fields in Fukushima, over. 70 km away from Hakodate, in Oct. 1960 ; 21 clitellate obtained from the same locality at Hachiman-cho in Oct. 1960. External characters : Length 140-200mm, breadth about 6-8mm, number of segments 100106. Prostomium epilobous, without posterior transverse demarcation. Color in fresh worms, dark reddish brown dorsally and light yellowish gray ventrally, except clitellum which is uniformly light orengish gray. 'Setal zones less pigmented, appearing slight grayish lines even in the preclitellar region. The clitellum entire, in XIV-XVI, as usual in the genus, without intersegmental furrows and seta in fully developed ones, Setae. moderate in size. Setal numbers as follows : 55-60/VI, 57-63/VII, 60-66/VIII, 63-68/XIII. Dorsal pores begin to appear in XII/XIII. Spermathecal pores located in 3 pairs on. intersegmental furrows V/VI, VI/VII and VII/VIII, in the ventro-lateral side, being about 2/5 of the circumference apart. Each spermathecal pore minute, found on a slightly coloured small area just in front of an intersegmental furrow. The area is, unlike so-called spermathecal papillae, not elevated from the general body surface and sometimes appeared as a depression (Fig. 1, A). Female pore single, midventrally on XIV. One pair of male porophores were observed in all specimens. They are relatively.
(3) Tokukichi Takahashi and Hideji Yamaguchi large and roughly elliptical or somewhat circular in shape, and situated ventrally in the chaetal line of XVIII, being their long axis transversal in position and separated about 1/3 of the circumference. Each porophore is elevated from the general body surface, having a transverse slit-like groove with radial folds in its central part (Fig. 1, B). Sometimes the groove widens to expose the male pore which is minute and placed on a small papilla (Fig. 1, C). Male pore setae were 14-21 in number. No genital papillae were observed in any segment of the pre- and post-clitellar regions. VI. VII. ;;; ;• •. XVIII. B Fig. 1. Plierethna coinmtmissima. A, Aspect of spermathecal pore in VI/VII ; B, Ventral view of XVIII, showing male porophores ; C, Male porophore in the right side, male pore being seen on a small papilla ; D, Spermatheca in the right side.. Internal structures : Septa generally moderate in thickness ; VIII/IX vestigial and only ventrally traceable, IX/X wanting, X/XI very thin, XI/XII-XIV/XV slightly thickened. Peptonephridia attached to the anterior face of V/VI and VI/VII. Hearts 4 pairs in X-XIII, but those in X frequently vestigial or reduced in the left or the right. side. Gizzard found between VII/VIII X/XI. Intestine begins to widen in XV. Intestinal coeca paired and arising from the intestine in XXVII, occurring as 6-9 fingershaped projections ; the most dorsal one prominently longer than the others which decrease gradually in length toward the ventrum. The end of the longest one reaches. usually in XXIV. Lymph glands lobular, and commence to appear in XXVII/XXVIII or XXVI/XXVII. Spermatnecae 3 pairs in VI, VII, and VIII ; ampulla large and roughly spherical in shape, having a thicker duct ; diverticulum tubular and longer the main portion in length, winding its central part (Fig. 1, D). Seminal vesicles very large, voluminously developed in XI and XII, their dorsal surface being slightly lobate ; those in XI are extending anteriorly about to IX, septum X/XI being pushed foreward. Testis sacs rather small in size ; the anterior sac low V-shaped and the posterior. 2—.
(4) Occurrence of Pheretima commiwissima (Goto et Hatai) in Hokkaido. forming a transverse sac. Pseudovesicles moderate in size, one pair in XIII, being. attached to XII/XIII. Prostate glands well developed to widen in 4-6 segments from XVI to XXII. They are usually trilobed, the middle lobe being smallest, and all lobes with numerous lobules. Remarks : Our specimens are identified with the present species from the following reasons.. Though the original description of the species (Goto and Hatai, 1899) is rather abbreviated, important characteristics of our specimens agree almostly with the original description and the notes on specimens identified with the species by Kabm-aki and. Misaka (1936). According to the original description, the intestinal coecum is in XXVI. But, it is situated arising in XXVII in our specimens and Kaburaki and Misaka's specimens. On the other hand, one of the present writers, the latter ascertained that it is also situated arising in XXVII in two specimensl) from Honshu, which have been refered to the present species, and that few difference is found between the specimens and the present material. Literature cited Got, S. and Hatai, S., 1899, New or imperfectly known species of earthworms. No. 2. Ann. Zool. Japan. Vol. 3, p. 23. Kaburaki, T. and Misaka, K., 1936, Plants and Animals in Nikko. p. 511 (in Japaneae), Kobayashi, S., 1941, The Outline of the distribution of terricolous Oligochaeta in the western territories of Japan. Zool. Mag. Vol. 53, p. 371 (in Japanese). Ohfuchi, S., 1947, Illust. Encyclop. of Japanese Fauna, p. 1360 (in Japanese).. 1) They were collected in Saitama Prefecture and have been sent from Prof. T. Adachi of Toyu Daigaku, in reply to our request through Prof. S. Ohfuchi of Tokyo Nogyo Daigaku. Many thanks must be offered to the gentlemen for their kindness.. g.
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