T06 GLOSSARY. 



Phrag'macone (Gr.phragma, a partition ; konos, a cone). The 



conical part of the internal shell of a belemnite, which is 



divided into chambers by partitions. 



Phre'nic (Gr. phren, the diaphragm). Relating to the dia- 

 phragm, as the phrenic nerve, which is supplied by the 



spinal cord to the diaphragm. 

 Phylactolae'mata (Gi.phulakteous, guarded; laimos, the throat). 



The division of the Polyzoa, the members of which 



possess an epistoma and a horseshoe-shaped lophophore. 

 PhylS'geny (Gr. phulon, tribe, species ; gems, lineage). A 



branch of Biology which attempts to gather the ancestral 



history of an animal from its development. 

 Physema'ria (Gr. phusema, a bubble ; L. ware, the sea). A 



group of low marine Metazoa. 

 Physiology (Gr. phusis, nature ; logos, a discourse). The 



science which treats of the various operations which take 



place in living beings, and which constitute life. 

 PhysS'poda (Gr. phusa, wind ; pous, podos, a foot). A group of 



small winged insects which live mostly in plants. 

 Physo'tomi (Gr. phusiao, I inflate). A group of Teleostean 



fishes in which an air-bladder is nearly always present. 

 PhytS'phaga (Gr. phuton, a plant; phago, I eat). A division 



of the Edentata which comprises all the vegetable-feeding 



forms. 

 Pi'a ma'ter (L. tender mother). The delicate, highly vascular 



membrane which forms the innermost of the three cover- 

 ings of the brain and spinal cord. 

 Pili'dium (Gr. pllidion, a small felt hat). A helmet-shaped 



body in which the larva of the Nemertidse is developed, 



and which is subsequently cast off. 

 Pine'al gland (L. pmea, a pine). A glandular body connected 



with the roof of the third ventricle of the brain, the 



function of which is at present unknown. 

 Pin'na (L. a fin or pinion). The expanded portion of the 



external ear ; also the primary divisions of a fern frond. 

 Pinnipe'dia (L. pinna, a fin ; pes, pedis, a foot). A division of 



the Carnivora which comprises the seals and walruses. 

 Pin'nule (L. pinnula, a little feather). The small lobes or 



leaflets of the frond of a fern, or of the leaf of any other 



plant similarly divided. Also each radiating process of 



the arms of a Crinoid. 

 Pis'ces (L. pisas, a fish). The class of the Vertebrata which 



includes the fishes. 



