MINUTE STEUCTUEE OF GILLS OF PALJIMONETES VAEIANS. 83 



the structure of these glands and of those of the Phronimidse 

 is very slight. Indeed, the latter may be considered as repre- 

 senting a stage in the development of the former. 



Eisig^ considers that two distinct series of glands occur in 

 Arthropods, the one series being homologous with the crural 

 glands of Peripatus, and the parapodial spiral glands of 

 certain Chsetopods, and being of ectodermal origin, the other 

 series being the nephridia. 



The spherical glands, which are now shown to occur in 

 every segment in Decapods, would seem to belong to the ecto- 

 dermal series, although the question cannot be finally settled 

 until something is known of their development. One has, 

 however, only to imagine a number of cells, such as the goblet- 

 cells of the leech, gathered into a cluster, one cell taking up 

 the function of a common duct, and such glands as those 

 which have been described in the present paper would be the 

 result. 



In conclusion, I should like to express my very best thanks 

 to Professor Weldon for his constant kindness and advice 

 during the progress of this research. 



* Eisig, "Die Capitelliden des Golfs von Neapel," 'Monographie der 

 Fauna und Flora von Neapel,' Berlin, 1887. 



