Notes on the morphology of the Tunîcata. 557 



may be a true one. The neural gland of Tunicates may be a double 

 structure, one part coming from the central nerve tube, the other 

 (represented by the gland of Salpidae and the lateral ducts of As- 

 cidia atra^ Ascidia marioni, Fhallusia and Polycarpa sulcata) arising 

 from the pharynx wall. I have demonstrated such an origin for the 

 gland in the Salpidae. One might conceive, then, that the gland 

 of neural origin in the Tunica ta is represented in the Verte- 

 bra ta by the infundibular gland, while the gland of pharyngeal origin 

 in the Tunicates would find its homologue in the hypophysis proper in 

 the Vertebrates. It would not be very difficult to imagine the changes 

 necessary to transform the Tunicate gland into the Vertebrate two- 

 fold structure. Yet it seems hardly natural that an homology founded 

 on such a basis should be generally accepted by zoologists as esta- 

 blished and should be so described in standard text-books. I believe 

 that Julin's suggestion should stand only as a suggestion a most 

 valuable one, which should be taken into account in all our thinking 

 upon the phylogeny of the Vertebra ta, but a suggestion the truth 

 of which, while perhaps probable, is still insufficiently established. 

 Reference to the neural gland of Tunica ta as the hypophysis as- 

 sumes too much. 



Section II. 



The Histology of the Brain and Ciliated Funnel in 

 lasts cordiforinis-i^onaria, 



Plate 40, Figs. 89—91. 



Having been fortunate 3 years ago in obtaining living Salpas 

 of this species, I was able to make a few observations upon the 

 shape of the cells in the brain and the ciliated funnel, studying them 

 by maceration methods. The parts desired were placed in Haller's 

 mixture of acetic acid, glycerine and water, tinged with methyl green, 

 until they became sufficiently softened, when by pressure and teasing 

 the cells were isolated. The eye of this species is degenerate, so that 

 it does not offer a favorable subject for study by this method. 



The cells of the brain are well-known to be of two somewhat 

 distinct sorts in Salpa. Most of the periphery of the ganglion con- 

 sists of thickly crowded small cells with small nuclei, while in the 

 horizontal zone from which the nerves arise we find much larger 

 cells with larger nuclei. In sections one can occasionally see that 



