391 Rev. W. Houghton on the Occurrence 



O' 



This species appears to have been first noticed by 0. F. Miiller 

 in his ' Wiirmern des sussen 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. i. 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 blind, 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. iii. 1. p. 363) appears to have 

 been the first to separate this Annelid from the genus Nats, 

 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 (Diet, des Sc. Nat. lvii. 498, atlas, pi. 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 i 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 



