HIRUDO. 9 



PLATE I. 



FIG. 6. Group of Udonella from the Leech, natural size. 



7. A specimen magnified ; anterior, a ; sucker, b. 



8. Another. 



9. Anterior extremity of the Udonella, more highly magnified. 



10. Supposed capsule pertaining to the Udonella, magnified. 



11. Capsules of the Hirudo muricata, deposited on a shell. 



12. Young Leech, bred from the capsule, extended. 



13. Young Leech, bred from the capsule, coiled. 



14. Capsule, recently produced in confinement, still almost white. 



15. Capsule, produced in confinement, darkened with age. 



2. HIRUDO VITTATA The Belted Leech. Plate I. Fig. 16. 



Length above two inches, breadth three lines, thickness one line ; 

 body flattened, smooth upper surface, slightly convex. Anterior extre- 

 mity formed as a cup, occasionally flattening, and applying like a disc to 

 other substances ; posterior extremity broad, thin, and large in propor- 

 tion to the animal, employed as a sucker. That of a very large speci- 

 men of the Hirudo mttata, one extending eight or nine inches, was of 

 smaller diameter. The body is chiefly whitish and speckled, somewhat 

 transparent, so as to expose ten pair of cells within. Ten projections, like 

 hemispherical blisters, border each side of the animal, rising and falling 

 as if by respiration ; no eyes could be found. 



It generally remains erect on the broad or adhering sucker, often 

 waving to and fro. Plate I. fig. 16. 



Four specimens were obtained on July 23. Next morning I ob- 

 served what I supposed six capsules produced in the course of the night, 

 and in three days, other three of larger size. In another vessel, con- 

 taining two specimens, eight of a similar description were produced. 

 Those subjects did not bear any resemblance to the capsule of the 

 Hintdo muricata, being only a minute spherical segment, nearly a hemi- 

 sphere, about the third of a line in diameter, and of dingy yellow colour. 

 On another occasion, nineteen of the same subjects were produced in a 

 vessel containing twenty-four leeches on the 20th of November. Their 



