APPENDIX 609 



writers {e.g., Woodburn, Escoyez) deny the presence of centrosomes 

 and consider the blepharoplast to be an organ of cytoplasmic origin. 

 Ikeno also describes a peculiar body to which he gives the name 

 " Nebenkorper, " whose nature is problematical. 



Humphrey (i) has studied the spermatogenesis of Fossombronia, 

 where he decided that the blepharoplast arose de novo in the cyto- 

 plasm. In Fossombronia the final division of the sperm-cells is 

 diagonal, as it is in Marchantia, and the spermatids appear triangular 

 in shape. In Fossombronia there is a structure suggestive of the 

 "Nebenkorper," but Humphrey states that in this case it forms part 

 of the spermatozoid. In other Hepaticae, e.g., Calycularia, Pellia, 

 the spermatids are nearly hemispherical. 



In a recent paper, Wilson (2) states that he believes the blepharo- 

 plast in Pellia to be derived from a centrosome, and he also describes a 

 globular body " limosphere," and an "accessory body," as present 

 in the spermatid, but was not able to determine their origin. 



All agree that the cilia arise from the blepharoplast, which very 

 early assumes a position at the periphery of the spermatid. Most 

 authors state that the elongated thread which connects the cilia with 

 the nuclear portion of the spermatozoid is formed by the elongation 

 of the blepharoplast itself ; but Wilson thinks that the greater part 

 of the thread does not belong properly to the blepharoplast. 



The bulk of the body of the spermatozoid is undoubtedly formed 

 from the nucleus of the spermatid which becomes homogeneous in 

 appearance and elongates to form a more or less coiled body. 



P. 20. In his resume of the inter-relationships of the Bryophytes, 

 Cavers (9) proposes the establishment of a third order of Hepaticae 

 (exclusive of Anthocerotales), the Sphaerocarpales, which is to a cer- 

 tain extent intermediate in character between the Marchantiales and 

 the Jungermanniales. Sphosrocarpus (see Chap. Ill) is on the whole 

 the simplest known Liverwort, and Cavers' view is that the family 

 Sphaerocarpacese is suflSciently different from the other two orders to 

 warrant the establishment of a third order, Sphaerocarpales, which is 

 more primitive than the other two. 



P. 21. It has been proposed to recognize two other families 

 intermediate between the Corsiniaceae and the Marchantiacea2, viz. 

 the Targioniaceae, comprising Targionia and Cyathodium, and the 

 Monocleacese with the single genus Monoclea. The difJerences be- 

 tween these genera and the typical Marchantiaceas are probably suffi- 

 cient to warrant the establishment of these famihes. (See Cavers 



(9).) 



39 



