398 



ON THE PETEELS COLLECTED DURING 



Zool. Cball. greater number of the last tracheal rings, forming together the framework 

 pS.. 33! f tne lower larynx. In most cases the last tracheal ring bears a well- 

 marked antero-posterior pessular bar. 



It is in the genus Pdecanoides (figs. 3, 4) that the typical construction 

 of the syrinx of the Tubinares is seen in its simplest form ; it will, 

 therefore, be described first on the present occasion. 



Fig. 3. 



Syrinx of Pelecano'ides urinatrix, from before.* 

 Fig. 4. 



The same, from behind. 



The last tracheal ring is complete in front, and not modified in shape ; 

 posteriorly it is produced downwards into a well -developed pessulus, so 

 forming a complete three-way piece. The first bronchial semi-rings are 



* This and the succeeding figures of the syrinx of the Tubinares have been drawn 

 as nearly as possible of one uniform size, irrespective of that of the originals, and are 

 also slightly diagrammatic. The bronchial rings are numbered from 1-5 ; the tracheal 

 are marked 0, 00, 000, &c., in the reverse direction. 



