Observations on the Hirudo complanata, and Hirudo stagnalis : now formed into a distinct genus under the name, Glossopora / by Dr. Johnson.

  • Johnson, James Rawlins, -1840.
Date:
1817
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the Hirudo complanata, and Hirudo stagnalis : now formed into a distinct genus under the name, Glossopora / by Dr. Johnson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    daily notice for a period of at least six months, I may, I pre- sume, speak with some decision on this point. It may seem perhaps unnecessary to add, that I possess an elegant pre- paration, showing this tongue (protruded from the mouth) filled with mercury. It is of a cartilaginous structure, and admits of great flexibility. It is in length about one-eighth of an inch, and is seen, delineated (magnified) in Fig. 5. (PI. XVII.) The G. tuberculata, is about half an inch in length, but when fully extended, one inch. It is commonly found in rivulets, attached to pieces of wood, stones, &c. A delineation is given of its natural size, in a front and back view, in Fig. 1, 2, 3,4. It possesses great transparency, and has a fine glossy vitre- ous appearance. It is convex above, flattened beneath, and somewhat resembles a compressed pear, the tail being very broad, and the head tapering towards the extremity, in which may be seen six eyes, (Fig. 9. b) disposed in two longi- tudinal rows. The sides or margin of the body are ser- rated. The back is usually of a brown colour, with lighter or darker patches, ornamented in the middle with a double longitudinal row of white tubercles. (Fig. 9. c.) These tubercles are connected together by two black longitudinal lines, and are seldom apparent, unless the animal is at rest. The belly is generally of one uniform colour, chiefly grey, with a slight double black line running longitudinally in the centre. When this animal is in motion, (to which it is much averse, seldom quitting the spot on which it may be affixed,) it is observed to throw forward its head to the greatest point of extension, and then attach itself by means of the sucker ter-