short pedicels, lateral on the ultimate pinnules, ternately partite. Colour a 

 (lark brownish or full red, preserved or deepened in drying. The substance 

 is lirm and eartilaginous, and in drying the frond does not adhere to paper. 



A very rare and strongly-marked species, but one whose ^enus 

 cannot be correctly determined until the cystocarps shall be 

 found. I have hesitated whether to place it in Wrangelia, Ballia, 

 Callithamnion, or Ptilota ; and in choosing the latter genus for 

 its temporary location, I am guided more by general habit than 

 by distinctive characters. 



Though a very rare species, it has been found in three locali- 

 ties, first by myself, and more recently by two valued corre- 

 spondents. In naming it after one of my friends, I record the 

 fact, that it was from him that I received, though not the earliest 

 found, yet by much the most perfect specimen, and that from 

 which the drawing has been taken. I wish, too, here to express 

 to Mr. Hannaford my thanks for several small parcels of Algae 

 sent to me at different times. 



Fig. 1, Ptilota Hannafordi, — the natural size. 2. A pinna, with its oppo- 

 sing abortive pinnae. 3. Section through the stem. 4. Pinnule, bearing 

 tetraspores : — variously magnified. 



