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PROEESSOR ALLMAN ON THE STRUCTURE 
The blastostyles (a, a, a , a) spring from that portion of the hydranth which lies 
immediately below the tentacles. They form a dense group, surrounding the body 
on all sides. They are usually somewhat clavate, or of -an elongated fusiform shape, 
but are very contractile and vary much in form. Towards their free extremity they 
carry several small scattered capitate tentacles ; and at the proximal side of these are the 
gonophores {b, b, b), which belong to the type of simple sporosacs, and are large, of a 
globular form, and carried on very short peduncles, which spring without any regular 
arrangement from the sides of the blastostyle. 
From the same part of the body there also spring numerous very extensile filiform 
organs resembling tentacles ( c , c,c). These arise for the most part close to the base of 
a blastostyle, where they occur mostly in pairs, though sometimes singly. They termi- 
nate distally in a truncated sncker-like extremity. It will be afterwards seen that 
these organs, which have been hitherto entirely overlooked, perform an important 
function in the economy of the animal. I shall designate them by the name of 
“ claspers.” 
The section of the body from which the blastostyles and claspers spring is usually 
somewhat swollen, and is marked by close longitudinal shallow furrows. After con- 
tinuing naked for some distance beyond the proximal limit of the gonosome, the body 
bends at right angles to itself, becomes clothed with a chitinous perisarc (<?.),' and fixes 
itself by the extremities of short truncated processes (e) to some solid support. 
The general colour of the animal is a pale straw-colour. The tentacles are almost all 
tipped with a brownish-purple spot, the same colour sometimes extending over the 
greater part of the tentacle, and generally also spreading in clouds and streaks over the 
tentacula-bearing portion of the body. The gonophores are of a dull white, with their 
distal poles encircled by a ring of purple pigment dots. 
The genus Myriothela was instituted by Sars for an animal which he obtained off the 
coast of Norway, and described under the name of Myriothela arctica*. He has given 
an accurate, if not altogether adequate description of its external characters, and has 
correctly referred it to the Hydroida. Mr. W. Stimpson, however, has pointed outf that 
the Myriothela arctica of Sars is identical with an animal which Fabricius, in his c Fauna 
Groenlandica,’ has described under the name of Lucernaria jyhrygia, and for which De 
Blainville afterwards constituted a new genus, to which he assigned the name of Cande- 
labrum. He Blainville, however, though he could have no difficulty in seeing that 
Fabricius’s animal was not a Lucernaria, had notions of its affinities even less exact 
than those of the celebrated author of the ‘ Fauna Grcenlandica.’ He could see no 
relations between it and the Coelenterata, and asserts that its affinities are with 
Sipunculus. 
If the laws of priority were rigidly enforced, Sars’s name must yield to that proposed 
by I)e Blainville ; but as it is plain that De Blainville knew nothing of the animal 
* Sabs, Zoolog. Reise i Lofoten og Einmarken, 1849. 
t See Agassiz, Cont. Nat. Hist. U. S. vol. iv. p. 341, note. 
