filum than to any other, although very different in external habit. 

 Kiitzing even places it in the genus Chorda, nor is there any 

 very decided character beyond outward form to distinguish it. 



The analysis now given shows that there is also a strong 

 natural affinity to the genus Chordaria, so strong that I am 

 induced to propose the removal of both Chorda and Adenocystis 

 from the Laminariecs, where they are placed by Agardh, to the 

 Chordariea, with which, in structure, and the nature and evolu- 

 tion of the spores, they more closely agree. In external aspect 

 also they accord better with Chordariece than with any genuine 

 Laminarian genus. 



Adenocystis Lessonii is interesting as an Antarctic plant, ex- 

 tremely abundant on the inhospitable coasts near Cape Horn, 

 and one of the few Algae discovered on the still more barren 

 Cockburn Island, and which reaches its northern limits near 

 the southern point of Tasmania, In the Antarctic regions Dr. 

 Hooker usually found it in rock-pools ; but at Port Arthur it as 

 often grows on the bare rock. When dried up, on the recess 

 of the tide, its bag-like fronds become inflated and glossy. 



Fig. 1 . Fronds of Adenocystis Lessonii, on a piece of rock, — the natural size. 

 2. Small portion of the membrane, showing the glandular spots. 3. Sec- 

 tion through the membrane. 4. Spores and peripheric filaments : — the 

 latter figures variously magnified. 



