104 GLOSSARY. 



muscular fibres of their walls, and by which their contents 



are urged onwards. 

 Peristeromor'phse (Gr. peristera, a pigeon ; morphe, form). 



The pigeons, a group of carinate birds. 

 Pe'ristome (Gr. peri, around ; stoma, a mouth). The rim 



which surrounds the opening of the gullet in the Vorti- 



cellse. In the Crustacea, the space between the pterygo- 



stomial plates and the antennary sternum. 

 Peristo'mium (Gr. peri, around ; stoma, a mouth). The somite 



of the body which contains the mouth. 

 Peritone'al sac (Gr. peri, around; teino, I stretch). The 



portion of the vaso-peritoneal vesicle which in the Holo- 



thuridea is developed into the peritoneum. 

 Peritone'um ") (Gr. peri, around ; teino, I stretch). The serous 

 Perito'neum } membrane which lines the abdominal cavity, 



and invests its viscera. 

 Peritri'cha (Gr. peri, around ; thrix, trichos, hair) . A group 



of the ciliated Infusoria, in which the cilia form a belt 



round the body. 

 Peronae'us bre'vis (Gr. perone, the fibula ; L. brevis, short). 



One of the ventral muscles of the fifth digit of the pes. 

 Peronae'us ter'tius (Gr. perone, fibula ; L. tertius, third). A 



muscle passing from the dorsal face of the fibula to the 



fifth metatarsal of the foot in man. 

 Perene'o-calea'neus inter'nus (Gr. perone, the fibula ; L. calx, 



the heel; zV/^r^z/j, internal). A small occasional muscle 



arising from the fibula, and inserted into the calcaneum. 

 Perone'al (Gr. perone, the fibula). A term sometimes applied 



to the fibula ; therefore also the name given to the arteries, 



veins, and nerves supplying this region of the leg. 

 Perospondy'lia (Gr. spondulos, a vertebra). Applied to those 



Reptilia which have dorsal vertebrae with double tubercles 



in lieu of transverse processes. 

 Pes (L. foot). The terminal portion of the hind limb which 



in man forms the foot. It includes the tarsus, metatarsus, 



and digits. 

 Pes accesso'rius (L. pes, a foot; accessw, an addition, increase). 



A smooth eminence in the posterior cornu of each 



lateral ventricle of the brain. 

 Pes hippocam'pi (L. pes, foot; Gr. hippos, a horse; kampto, 



I bend). Another name for the hippocampus major of 



the brain which see. 

 Pe'tal (Gr. petalon, a leaf ). A leaf of the corolla of a flower. 



