PONTOBDELLA. 41 



Obs. I am inclined to believe that P. muricata and verrucata are 

 distinct species, to be distinguished by the assigned characters in 

 general readily, although I have seen a few specimens where some 

 hesitation might exist as to their specific designation. When alive 

 both are of a dull green colour. There are twelve rings between the 

 oral sucker and the clitellus, and three of these are more prominent 

 than the intervening ones. The clitellus is composed of eight un- 

 equal narrower rings. Behind the clitellus there are about forty-six 

 rings, divided into sets of three each by the intervention of a nar- 

 rower and less papillose ring. Sometimes from distension this divi- 

 sion into rings becomes obliterated, or nearly so. 



(a) Berwick Bay, Br. Johnston. 



(b) South coast of Devon, G. Montagu. 



(c) Abergsteyth, Rev. J. Henslow. 

 {d) Falmouth, J. Cranch. 



(e) No locality. 



3. P. areolata, body narrowed forwards into a taper annulated neck, 

 smooth and even, indistinctly or obsoletely ringed; oral sucker 

 small, one- half the size of the anal, the rim plain. Length 3" ; 

 breadth 5'". 



Pontobdella areolata. Leach in Brit. Mus. Coll. Blainv. Diet, des Sc. 



nat. Ivii. 557. Moq.-Tandon, Monogr. 290. pi. 2. f. 12. Dies. Syst. 



Helm. i. 439. 

 La Sangsue areolee, Blainv. Diet. cit. xlvii. 242; Monogr. 40. 



Hab. The English coast : rare. 



Obs. The specimen labelled "P. areolata'^ in the Mus. Coll. is 

 one of P. muricata, and the specimen which I presume to be P. 

 areolata has no name affixed to it. It is in bad condition, but from 

 its flexibility and flatness it may be inferred that the leech is soft 

 when living. It is at once seen that it diflfers from every variety of 

 P. verrucata by the gradual manner in which the body tapers from 

 below the middle to the head. There are no distinct rings excepting 

 on the neck. Over the body generally there is an appearance as it 

 were of subcutaneous depressed warts which give, in some partial 

 spots, the areolated appearance whence the name has been derived. 

 The colour, in spirits, is a dull yellowish-grey. It seems a distinct 

 species. 



(a) Plymouth Sound, Charles Prideaux. 



** Segments and rings subequal, smooth : no clitellus. 



4. P. laevis, skin smooth, obsoletely annulated; body narrowed for- 

 wards ; anal sucker comparatively small, less than the oral or sub- 

 equal. Length 4-6". 



Hirudo (Pontobdella) Isevis, Blainv. Diet, des Sc. nat. xlvii. 243, 

 Atlas Sangsues, f. 3. 



