82 



SIXTEENTH KEPORT ON THE CABINET OF NAT. HISTORY. 



The specimens designated by Mr. Vanuxem the ^^ Retort fiicoid,^^ are 

 clearly parts of the spiral forms already described, but growing irregular- 

 ly so as to give a greater expansion on one side ; or from pressure on the 

 opposite side, that part of the frond has been contracted or crushed. 



The annexed figure from the Report of Mr. Vanuxem, when compared 

 with those on Plate 2, will show the same or a similar mode of growth. 



Fig. 4. 



