LINDSAY, ON THE PROTOPHYTA OF ICELAND. 197 
2. The antennal muscle has a fascia composed of this 
tissue, and this sheath Dr. Moxon has called the sarcolemma. 
3. The antennal nerve has a similar investment, known as 
the neurilemma. 
4. The neurilemma of the antennal nerve is continuous 
with the fascia of the antennal muscle. 
5. The antennal nerve is a bundle of nerve-fibres. 
6. The nerve-fibres which are undefined within the neuri- 
lemma remain undefined after they have left that sheath. 
7. The ‘ pellucid material” is the mass of nerve-fibres. 
8. The individual fibres, after they have left this pellucid 
mass, have not been demonstrated. 
9. The nuclei are probably the nuclei of nerve-fibres. 
10. ‘The antennal nerve breaks up and is distributed with- 
in the muscle-fascia, but not within the sarcolemma. 
On the Proropuyta of IceELAnp. By W. Lauper Linpsay, 
M.D., F.R.S. Edin., &c. 
WHEN we consider the geographical position of Iceland, 
the extent of its traffic with Britain and Scandinavia, the 
abundance of the localities which it contains affording suitable 
habitats for such forms of vegetation, it is not a little remark- 
to find its Flora extremely defective in some of its depart- 
ments, and notably so in that of the Protophyta and the lower 
or Chlorospermous Alge. 
Iceland has been for years in constant and regular com- 
munication by steam (during the spring, summer, and 
autumn months, at least) with Denmark and Britain.* The 
island belongs to Denmark, a country which possesses most 
zealous and accomplished naturalists ; it has been repeatedly 
visited by Scandinavian, French, and other continental 
men of science ; and has been the field of at least one Natural 
History Expedition, the fruits whereof have been published 
in a series of magnificent volumes.t It is now one of the 
fashionable summer excursion-fields of British naturalists 
and tourists, who have during the last ten years published 
* “Tceland a new Field for Tourists,” ‘ Perthshire Advertiser,’ Aug. 2nd 
and 9th, 1860. 
_ } ‘Voyage en Islande et au Groenland executé pendant les années 1835 et 
1836 sur la Corvette La Recherche ; publié par ordre du Roi sous la direc- 
tion de .M. Paul Gaimard, Président de la Commission Scientifique 
d’Islande et de Gréenland.’ 6 vols. folio, with an atlas, Paris, 1840. 
