オヤマミミズ

＜原記載（クリックして展開）＞

 

External Characters:

　　Six specimens of this species were examined; the body length, width and number of segments are as follows;

　　Average of body length 238 mm (217-278 mm).

　　Average of body width 7 mm (6-7 mm) at segment XII.

　　Average of number of segments 121 (116-123).

　　The colour is dark brown on the dorsal side, and light grey on the ventral side.

　　The spermathecal openings are of four pairs in V/VI, VI/VII, VII/VIII and VIII/IX.  The pores have semicircular-shaped appertures.

　　The proportion of the intersegmental circumference position of the spermathecal openings, to the circular distance between two spermathecal openings ventrally are as follows; ratio of circumference and circular distance between two spermathecal openings 3-3.1.

　　The first dorsal pore is in XII/XIII.  Clitellum occupies 3 segments XIV, XV and XVI, intersegmental furrows lacking, as usual without setae.

　　The genital papillae are round-shaped and 0.5 mm in diameter, in some specimens a pair of genital papillae are found situated in front of the chaetal line of segment XVIII, more towards the middle than to the position where the male pores are situated, as is shown in Text-fig. 10, 3.  The genital papillae have not been recognized in the spermathecal region.

　　The first segment lacks the setae and begins on segment II.  Setal numbers of the worms are as follows; 38-40 in VII, 43-44 in XX.

　　The male pores are situated on the lateral border of the chaetal line of XVIII, and separated by 8 setae (8, 8, 8, 9).  Sometimes, in this species the male pores are recognized to be absent.  The margin of the male pores are almost parallel to the body surface.

　　This species shows close resemblance to Pheretima grossa in some external characters, but the positions and the diameters of genital papillae serve in easily distinguishing that species from the present one.

 

Internal characters:

　　The spermathecae are situated in the segments VI, VII, VIII and IX.

　　The spermathecal ampulla is smooth and ovoidal elongate in shape, about 2 mm long and 1.2 mm broad; duct long and stout, about 1.2 mm long, and gradually narrowed in the parietes.  Although the diverticulum are not present and recognizable as in the other species of this genus, a pair of glandular masses are recognized, and they open in the terminal portion of the duct, this mass seems to be a substitute organ to the diverticulum.  Text-fig. 10, 4, B shows this organ's situation and correlation to the duct and ampulla.

　　Ovaries in XIII.  Oviduct in XIV.

　　The prostate glands are entirely lacking in some specimens but are found on the right side only in other, but the development is poor, Text-fig. 10, 5, shows the degree of development.

　　The intestine begins in segment XVI and a pair of the intestinal coecum begins from segment XXVII.  The coecum is a single projection, extending from segment XXVII into the mid of segment XXIII, as is shown in Text-fig. 10, 6.

　　The septa are thickened in V/VI, VI/VII, VII/VIII and X/XI, XI/XII, XII/XIII, XIII/XIV much thickened, VIII/IX and IX/X wanting.  One pair of the ovaries hangs behind septum XII/XIII.

　　The seminal vesicles are situated in XI, XII, as is shown in Text-fig. 10, 7, the development is of a lower degree compared to the other species of this genus.  Owing to very thickened and developed septa XI/XII and XII/XIII these glands are embedded in them.

 

Remarks:

　　In general outline, this worm resembles Pheretima grossa, but the number of the genital papillae in the neighbourhood of the male pores serve in easily distinguishing that species from the present one.  In Pheretima grossa, a pair of them lie close to the male pores.  Segments XIX, XX, XXI, or XIX, XX, XXI, XXII, in Ph. grossa each possess a pair of genital papillae behind the setal line.

　　In the Pheretima grossa, the diverticulum of the spermatheca is very thick, tubular and sharply coiled, and forms an enlarged chamber at the ental end about 2 mm long; usually a diverticulum opens in the terminal portion of the duct.  But in the present species, the diverticulum in not present as in the other species of this genus, but the glandular masses of a pair, are or more or less recognizable, and they open in the terminal portion of the duct.