286 LIONEL JAMES PICTON. 



combination as to be easily removable by hydrochloric acid. 

 In tissue treated for ten hours with nitric alcohol the granu- 

 lations are very markedly stained by either method.^ 



In Stylaroides hirsutus the heart-body folds have 

 become rounded or flattened strings, which may run for con- 

 siderable distances independently of one another. The cells in 

 sections of 4 ju are clearly defined, and usually occupy the 

 whole thickness of a strand, though occasionally a lumen is 

 left. Except for brown granules, some of which are large 

 and contain a dark central spot, there are few cell-contents. 



Cunningham describes the cords in Trophonia plumosa 

 as hollow, and formed of three layers of cells, the most 

 internal of which is composed of spherical elements which 

 project irregularly into the lumen as in a section of a nephri- 

 dium, which the whole structure much resembles. 



Horst studied the heart-body in Brada (16). He is struck 

 with the lack of demarcation between the cells : " Bei einem 

 jungen Examplare von Brada villosa war an der Peripherie 

 der Strange die Zellgrenze ziemlich deutlich, der centrale Theil 

 aber wurde gebildet von einer rait braunen Kornchen gefiillten 

 Grundsubstanz, worin keine deutlichen Zellen nachzuweisen 

 waren. Bei den erwachsenen Individuen zeigen die Strange 

 auf dem Querschnitt nur ein unregelmassiges Netz von 

 Fasern, in dessen Knotenpuncten deutliche Kerne liegen, 

 wahrend in der durchsichtigen Grundsubstanz der Maschen 

 die braunen Kornchen zerstreut sind.'^ If " Faseru " means 

 cellular fibres, such an arrangement would be similar to that 

 above described in the medulla of Audouinia ; but, on the other 

 hand, if, as is more probable^ the so-called fibres are only cell- 

 walls seen in section, the arrangement agrees with that seen 

 in Stylaroides, which is characteristic of the Chlorhsemidse. 

 Haswell, however, who studied Australian Chlorhsemidse (15), 



1 In fresh heart-bodies a considerable amount of debris and a number of 

 crystals are noticeable. The forms of the crystals were not characteristic of 

 any special substance. Certain of them, hexagonal in shape, stained indigo 

 blue with iodine dissolveil in potassium iodide. Dr. Mayer pointed out to 

 me that they have no effect on polarised light. 



