Feb., 1908.] Polar Conjugation in the Angiospenns. 255 



type. Other teleosts in which the gustatory system is reduced as 

 compared with Ameiurus, as \^e\l as Cyclostomes, Elasmobranchs 

 and Amphibia must be studied with this particular point in view. 



In other forms the neural crest element is apparently fairly 

 constant in those nerves which contain gustatory fibres. The 

 small size of the special visceral component and of the placodes 

 in these types may account for the idea that the placodes arise in 

 response to the stimulus furnished by the contact of the neural 

 crest with the skin. The catfishes, however, are unique in the 

 size of their placodes and of their special visceral component. 



And if the IX ganglion should prove not to be a pure placodal 

 ganglion and the IX nerve of the adult does supply general 

 visceral surfaces, I still think the evidence very strong that the 

 placodal portions of these ganglia give rise to the special visceral 

 or gustatory fibres. 



And the special visceral system bears the same relation to the 

 general visceral that the Acustico-lateralis system bears to the 

 general cutaneous. 



ON THE ORIGIN OF POLAR CONJUGATION IN THE 



ANGIOSPERMS. 



John H. Schaffner. 



Various attempts have been made to explain the probable 

 origin of the remarkable structures and activities present in the 

 embryosac of the Angiosperms. These attempts, however, 

 resulted in mere hypotheses with few or no known facts in their 

 favor to recommend them for serious consideration. With the 

 recent great advance in our knowledge of the female gametophyte 

 of the Gymnosperms, due to the thorough work of a number 

 of zealous observers, has come the opportunity for a reconsid- 

 eration of the problem in the light of the new discoveries. Porsch^ 

 has done this in a very interesting and convincing paper in which 

 he presents very strong evidence for his views. 



He holds that the two synergids of the Angiosperms are neck 

 canal cells homologous with the neck canal cells of the Gymno- 

 sperm archegonium; that the oospheres of Gymnosperms and 

 Angiosperms are homologous cells: and that the upper polar,, 

 which is a sister cell of the oosphere, as determined by various- 

 observers for different plants and very definitely by the writer 

 for Erythronium,- is the homologne of the ventral canal cell of 

 the jGymnosperm archegonium. He holds further that the 



1 PoRSCH, Otto. Versuch einer phylogenetischen Erklarung des Embryosackes und der 

 doppelten Befruchtung der Angiospermen. Verlag von Gustav Fischer in Jena. 1907. 



2 ScHAFNER, John H. A contribution to the Life History and Cytology of Erythro- 

 nium. Bot. Gaz. 31 : 369-387. 1901. 



