and the reproduction of Leeches. 



13 



whether it be oviparous or not, though there is little doubt of 

 its being so. We have found its young, in an early stage, in 

 the same places as the adult, but never adhering to the pa- 

 rent. We have in our possession a singular variety of this 

 species, which has the posterior part and a large spot on the 

 abdomen of a pale flesh-colour. 



Sanguisuga medicinalis (Sav.), the medicinal leech. This 

 species is occasionally found in our neighbourhood, but is by 

 no means common. A dealer in leeches, residing in Norwich, 

 keeps a stock of about 50,000 leeches in two large tanks of 

 water, floored with soft clay, in which the leeches burrow. 

 On examining these tanks we found many capsules or ova de- 

 posits of the leech, which the owner (ignorant of their nature) 

 stated to be, at times, very numerous, but which he had neg- 

 lected and generally destroyed. The Austrian variety he 

 keeps in a separate tank, as he says it destroys the others. 



Nephelis vulgaris (Sav.). This species abounds in all our 

 fresh waters, and the brown capsules containing its ova may 

 constantly be found on the underside of the leaves of water 

 plants among the ova of the freshwater helices. We have kept 

 several of this species through the summer, and the following 

 are our notes as to the deposit of the ova and the development 

 of the young : — On the 2nd of June H. vulgaris deposited one 

 capsule containing ova; on the 5th another; on the 10th an- 

 other; and on the 15th two more, each of them containing 

 from seven to ten eggs. On the 22nd young appeared in the 

 capsule deposited on the 2nd, and on the 13th of July they 

 emerged from the capsule, so that in three weeks the young 

 were seen alive in the capsule, and in six weeks were fully 

 developed and left the capsule. 



Examining the young of this species under a power of about 

 sixty linear, Ave detected a Cypris and four specimens of a 

 common rotiferous animalcule in its stomach, one of the ro- 

 tifera being still alive. 



Nephelis tesselata ? In June last we captured in the river 

 at Costessey in this county a single specimen of a leech which 

 nearly agrees with the descriptions given of this species. It is 

 described by Blainville as follows : — " Body elongated or oval, 

 eighteen lines long, with eight eyes in a double longitudinal 

 series ; ash-coloured, with orange or whitish-coloured spots 

 above, the sides marked with white or partly gray and partly 

 orange-coloured spots ; the abdomen gray, with two round 

 spots in the middle." 



Our specimen is nearly cylindrical, about an inch long, the 

 posterior disc larger than the anterior ; eight eyes, in two rows 

 of four each ; colour green, with two indistinct, whitish, Ion- 



