1913] Gcc: Behavior of Leeches 201 



monograpliic des sangsues meclicinales (1857). Within a period 

 of one year (185-1) Busquet, Permond, and Laurens each pub- 

 lished a somewhat extensive monograph on the subject of leeches. 

 This fact is an excellent indication of the interest taken in leeches 

 at that time. The volumes of the last four authors .just men- 

 tioned have not been available, and, consequently, little can be 

 said here with regard to the general nature of these contributions. 



So far as I have been able to determine, the most significant 

 of the earlier writers is Moquin-Tandon, who in his Monographie 

 de la faniiUe des hirudinees (1827, 1846) considers the sum 

 total of the literature previous to his time, and di-seusses in a 

 very interesting way the structure, habits, and classification of 

 leeches, and to a considerable extent their use in medical practice 

 and the breeding of them for commercial purposes. This volume 

 contains a twenty-four page bibliography of the earlier liter- 

 ature, the titles extending back as far as the latter half of the 

 seventeenth century. In the numbers of references on leeches 

 which have been examined in connection with the work presented 

 in this paper, none of the earlier writers has been found to be 

 quoted nearly to the same extent as has Moquin-Tandon. 



Brandt and Ratzeburg (1833) in their Medkinische Zoologie 

 consider at some length the classification, anatomy, and the use 

 of the blood-leech in the medical practice of the early part of 

 the nineteenth century. 



Houghton (1863) discusses his observations on the breeding 

 habits and general behavior of the Glossiphonidae. Certain 

 species of this family he describes as "incubating" their eggs; 

 others as carrying the eggs attached to the ventral surface of 

 the body, and later the young in the same position. Of Glossi- 

 phonia tessulata he observes: "I have counted a hundred and 

 twenty young ones attached to the parent. The young for some 

 little time after they are perfectly formed continue tied to their 

 'mother's apron-strings,' which they generally leave when they 

 are about six weeks old." He correctly observes that leeches of 

 this family "are incapable of swimming and move from place 

 to place like the caterpillars called geometric." A somewhat 

 later article (1863) by the same author, entitled "Leech-Lore," 

 has been quoted in part in a preceding paragraph. 



