MYBIAPODA. ANNELIDA. 159 



MYRIAPODA. 



SCOLOPENDRA. The mouth of the Scolopendra is composed of a square- 

 shaped lip, of two mandibles, of two palpi, or small foot jaws, and of a 

 second lip formed by another pair of dilated foot jaws, which are joined to- 

 gether at their commencement. The latter are the organs which constitute 

 the formidable weapons of the animal. The poison gland is lodged in the 

 interior of these organs towards the base. It is oval, oblong, and provided 

 with a long, narrow excretory canal. The forceps terminate in a strong, 

 pointed, movable hook ; the claw is provided with a small oblong aperture 

 on its under surface, which allows of the exit of the poison. (Moquin-Tan- 

 don.) 



S. scopoliana, Europe ; S. heros, Texas. 



ANNELIDA, 



HIRUDO (Leech). Sub-class Discophora. Order Hirudinea. 



Characters. Elongate-articulates, with flattened bodies, narrowed ante- 

 riorly, broadened posteriorly, composed of ninety-five equal and distinct 

 rings, which project at the sides. The dorsal surface is marked with six 

 parallel longitudinal bands of a reddish or brownish hue, spotted with black, 

 continuous or intercepted, and sometimes reduced to mere points. The ven- 

 tral surface is either of a uniform color or spotted with black, and bordered 

 on each side by a straight or undulating line of the same color. The ante- 

 rior extremity is provided with an oral sucker, having an acuminate upper 

 lip. The posterior extremity bears a round, obliquely placed sucker, at the 

 base and upper part of which is the anus. Within the mouth are three pairs 

 of jaws, furnished with minute teeth. The eyes are ten in number, small 

 they are placed on the upper lip, where they form a curved line, the six an- 

 terior being the largest. Leeches are androgynous. The sexual orifices are 

 placed on the anterior third of the belly; the male orifice between the 

 twenty-seventh and twenty-eighth ring, and the female five rings farther 

 back. The first is a minute pore surrounded by a thickened margin ; the 

 second, a small transverse slit. 



H. medicinalis (Gray leech), Linn. Body olive green mixed with gray. 

 Six rusty red longitudinal stripes mark the dorsal surface. The sides are 

 olive green ; the belly is spotted with black. 



Habitat. Northern Europe and certain parts of northern Africa. 



H. officinalis (Green leech). Body of a clear olive or green color. Dor- 

 sal surface distinguished by six rusty red longitudinal bands, generally con- 



