39 4 Rev. W. Houghton on the Occurrence 
This species appears to have been first noticed by O. F. Miiller 
in his ‘ Wiirmern des siissen und salzigen Wassers,’ pp. 90- 
102, under the names of “ die blinde Naide” and “ das Blumen- 
Thier.” In tab. 5, this writer gives several figures of this An- 
nelid in various positions, which on the whole are very fair repre- 
sentations of it. In the ‘ Vermium terrestrium et fluviatilium 
Historia,’ vol. 1. p. 22, Miiller notices this worm under the appro- 
priate name of Nats digitata, abandoning the name he had pre- 
viously given it, as the epithet b/ind, being applicable to other 
worms of this family, could not be considered to constitute a 
specific difference. Turton (Brit. Faun. 137) mentions this 
species under Miiller’s latter name, as belonging to our own 
fauna ; and notices of it are given by Stewart (Elem. i. 391) and 
Pennant (Brit. Zool. iv. 98, ed. of 1812), but it does not appear 
that any of these authors had ever seen a living specimen: 
hence Dr. Johnston’s remark, “ The evidence on which this spe- 
cies has been introduced into the British fauna is unsatisfactory.” 
Oken (Lehrb. der Naturg. Th. ii. 1. p. 363) appears to have 
been the first to separate this Annelid from the genus Nais, 
forming what he terms the genus Proto; and Oersted (Kroy. 
Tid. iv. 2. p. 133) notices it under the name of Proto digitata. 
See also Blainville (Dict. des Sc. Nat. lvii. 498, atlas, pl. 1 fig. 1). 
Grube (Die Familien der Anneliden, p.105) proposes Dero as 
the name for this genus, and demurs to the Proto of Oken, as 
being one of uncertain derivation: but unde derivatur Dero? 
I have seen the Proto digitata but on one occasion, and was 
much puzzled, at the first sight of this novel worm, as to what 
kind of creature I was beholding. Having taken home and put 
into a glass vessel a small piece of submerged stick which was 
covered with the commonest of our native freshwater Polyzoa 
(Alcyonella fungosa), my attention was soon drawn to some 
pink-coloured objects, about 2 lines in length and 3 line 
in breadth, projecting from the surface of the fungoid mass ; 
the upper end was split into six or eight unequal, digitiform 
segments, broadest at the base and gradually narrowing to the 
apex. These segments were ciliated, and doubtless are branchial 
in their functions. With Miiller, I imagined that the object I 
was beholding was the head and upper portion of the animal, 
especially when, upon tapping the glass vessel, the creature sud- 
denly disappeared, concealing the whole of that part of its body 
within the thick and entangled filaments of the polyzoon, re- 
minding one of the similar action observed in the Melicerta. 
Upon further examination, however, I soon discovered that the 
portion I was looking at was the tail extremity, and that. the 
anterior part was hidden within the interstices of the coencecium 
of the Alcyonella. The ciliated segments are in the position 
