HIRUDO. 11 



3. HIRUDO ANCEPS. 



There cannot be any doubt of the genus to which the two preced- 

 ing species belong. It is otherwise with the present subject, which is 

 introduced here provisionally, for its place rather seems intermediate 

 between the Hirudines and the Vermes more nearly approaching the 

 former. 



Above sixty years have elapsed since the animal was introduced as 

 a leech to his fellow naturalists by Otho Frederic Miiller, under the 

 name Hirudo grosta. It was received as such for a long time unchal- 

 lenged, but M. Moquin Tandon proposed, more than twenty years ago, 

 to exclude it from the genus. 



I speak with diffidence, from having been able to obtain only a 

 single specimen, probably a variety, as the reader who has an opportu- 

 nity of comparing Miiller's account with mine may allow. 



Length, when extended, nine lines, breadth three ; body tapering 

 slightly to the anterior extremity, which is obtuse. The posterior extre- 

 mity terminates in a sucker of considerable diameter, colour wax yellow. 



A waving intestine down the centre is perceptible. Two dull red 

 specks are indistinctly seen towards the anterior. 



The whole animal is of a very gelatinous aspect. A specimen of the 

 Cyprina Islandica and an Ascidia were among the same collection as the 

 Leech. I did not discover the latter until vitiation of the water had 

 ensued, when it was found somewhat weakened, adhering to the bottom 

 of the vessel containing them. However it recovered by careful treat- 

 ment. Plate I. fig. 22, Hirndo grossa at rest ; extended, fig. 23. I 

 could not ascertain its food. 



The animal was first observed by me on May 8. I cannot affirm 

 when or on what it was taken. 



On occasion of delineation, the artist thought internal spawn per- 

 ceptible. 



The creature became enfeebled on the 30th. Next day I believed 

 it dead, but erroneously. It had lost the faculty of adhesion on the 



