526 FRANK E. BEDDARD. 
It is a Naid furnished with long processes on the anterior seg- 
ments which lodge the dorsal sete. I shall refer more par- 
ticularly to the structure of these processes in describing a 
quite new type of branchiate Oligochetous Annelid which I 
propose to name. 
Branchiura Sowerbyi, nov. gen. et sp. 
In looking over some mud from the “ Victoria regia tank ” 
in the Royal Botanical Society’s Gardens, Regent’s Park, I 
found three specimens of an Annelid which struck me at once 
as probably new. It was remarkable for the unusual con- 
tractility of the body, which suggested a leech or a flat-worm 
rather than a Chetopod. For this reason it is impossible to 
give any accurate measurement; half an inch to three quarters 
is about its length. It consists of about 120 segments (there 
were 170 in the largest individual). Examined with a lens, 
the orange-coloured digestive tract traversed by the bright 
blood-vessels could be seen; and at the posterior end of 
the body a series of delicate dorsal and ventral pro- 
cesses. The position of these organs, which I shall presently 
give reasons for believing to be branchie, suggested the generic 
name ; the species I have great pleasure in associating with 
the name of Mr. Sowerby, of the Botanical Society. 
After carefully noting and sketching the principal features of 
the worm when examined alive under low and high powers of 
the microscope, | preserved one specimen with corrosive subli- 
mate and acetic acid, followed by gradually increasing strength 
of alcohol; the others with Perenyi’s solution—a much better 
reagent—for histological study. 
§ Branchie. 
The principal structure of interest in this worm is of course 
the series of branchial processes. These are apparent, when 
the worm is examined with a lens, as a delicate fringe which 
decks the last one sixth or one seventh of the body, giving it a 
feather-like appearance. There are altogether about fifty 
pairs of these processes, which are segmentally arranged, 1. e. 
