GLOSSARY. 



231 



f"'g- 34 —Skeleton of Hind-limb of 

 Bear, to illustrate the Plantigrade struc- 

 ture, r. Radius ; u. Uina ; t Tarsal 

 bones; in. Metatarsal bones; d. Digits; 

 ca. Calcaneum. 



PLACENTA (Lat., a cake). The organ by which in 

 the higher mammals the blood vascular system of the 

 embryo is brought into in- 

 timate connection with that 

 of the mother. 



PLANTIGRADE (Lat. 

 plaitla, the sole of the foot, 

 and gradior, to step or walk). 

 Applied to animals which 

 in standing and walking 

 touch the ground with the 

 entire sole of the foot, as 

 man, or with the parts cor- 

 responding to the sole of 

 the foot or palmof the hand. 

 See fig. 34. 



PLATYRRHINE (Gr. 

 platys, broad, and r/iis, 

 rhinos, the nose). Adj., be- 

 longing to the Platyrrhinse, 

 or the group of the Quad- 

 rumana in which the nose 

 has a broad middle partition and the nostrils directed more 

 or less sidewards. Noun, a member of the Platyrrhinse. 



PLIOCENE (Gr. pleios, more, and kainos, new). In 

 geology, the term applied to the most recent division of 

 the Tertiary rocks. See Geological Table, vol. i. p. 23. 



PLOUGHSHARE BONE. The name of a highly 

 modified sesamoid bone present in 

 the moles. See fig. 35. 



POLLEX (Lat, the thumb). The 

 thumb; the first digit of the hand 

 or fore-foot. See Digit. 



PREMAXILLA ( Lat. /r«, before, 

 and tnaxilld). The bone situated in 

 front of the maxilla; the bone in 

 which the upper incisors are set. 

 Also called Ititermaxillary or Inter- 

 maxillary Bone. 



PREMOLAR (Lat. prce, before, 

 and molar). One of the front cheek-teeth; more pre- 

 cisely, one of the cheek-teeth which appear in the milk 

 dentition and are replaced by others in the permanent 

 dentition. 



PRESTERNUM (Lat. prce, before, and sternum, the 

 breast-bone). The anterior portion of the breast-bone; 

 the manubrium sterni. 



PRIMARY. In geology, the term applied to the 

 older rocks from the Cambrian to the Permian inclusive. 

 Also called Palaozoic. See Geological Table, vol. i. p 23. 



PROBOSCIDEA (Gr. proboskis, Lat. proboscis, and 

 Gr. eidos, form). An order of mammals, the members of 

 which are furnished with a proboscis which serves as an 

 instrument for grasping and as an organ of touch; the 

 elephant order. 



PROBOSCIDEAN. A member of the Proboscidea. 



PROCESS. Specifically, in comparative anatomy, an 

 outgrowth, especially one of considerable length relative 

 to its breadth ; a prolongation, not a mere swelling, knob, 

 or excrescence. 



PRONATION (Lat. promts, having the face down- 

 wards). The act of rotating the lower arm in such a 



fig- 35- — Lower part of 

 the Fore-limb of a Mole. 

 se. Sesamoid ( plough - 

 share) bone. I.-V. Digits. 



manner as to turn the palm of the hand downwards: 



opposed to Supination. 



PROXIMAL (Lat. /r<7j;/«w, next). A term applied 

 to the part of anything nearest to the trunk or jwint of 

 origin; as the bone of the upper arm is articulated at its 

 proximal end to the shoulder-blade : opposite to Distal. 



PSALTERIUM (I^t. form oH}r. psalterion, the name 

 of a stringed instrument). Sanie as Liber. 



PYLORIC (Gr. pyldros, a gate-keeper). A term 

 ap|)lied to that part of the stomach where the pylorus or 

 opening into the intestine is situated : opposite to Cardiac. 



QUADRUMANA (I^t. quatuor, four, and manus, the 

 hand). The order of mammals comprising the apes and 

 monkeys : so called because very generally provided with 

 an opposable first digit both on the fore- and hind-feet. 



QUATERNARY (Lat. quatuor, four). In geology, a 

 term applied to all the rocks after the Pliocene. Also 

 called Post-tertiary. See Geological Table, vol. i. p. 23. 



RADIUS (Lat., a ray or spoke of a wheel). The bone 

 of the forearm which lies innermost when the palm of 

 the hand is laid flat, and the corresponding bone in the 

 fore-limb of a (juadniped. It corresponds to the tibia in 

 the leg or hind-limb of a quadruped. See figs. 17 and 34. 



RECTUM (Lat. rectus, straight). The terminal portion 

 of the intestinal canal. 



RENNET STOMACH. The abomasum, the fourth 

 or true digestive stomach in the complex stomach of 

 ruminants: so called from containing the juice which 

 enables it to coagulate milk. See fig. 37. 



RETE MIRABILE, plur. Retia Mirabilia (Lat., a 

 wonderful net). A branching net-work of small blood- 

 vessels in the course of a large blood-vessel. 



RETICULUM (Lat., a net). The second division of 

 the complex stomach of ruminants : so called from being 

 divided into small compartments or cells by means of 

 partitions crossing each other netwise. Also called 

 Honey-comb Bag. See fig. 37. 



RETRACTILE. Capable of being retracted. 



RETROGRADE DEVELOPMENT. In evolution- 

 ary language, a modification or process of modification 

 by which has been brought about a structure less highly 

 specialized than one believed to have existed in an 

 ancestral form. 



Fig. 36.— Skull of Hare. Obser\e the small upper incUois f behind the large 



functional ones i : c.p. Coronoid process : z.a. Zygomatic arch. 



RODENT (I^t. rodo, to gnaw, roderis, rodeniis, gnaw- 

 ing). A member of the Rodentia. 



RODENTIA. An order of mammals with incisor 

 teeth specially adapted for gnawing. See fig. 36. 



RUMEN (Lat., the throat). The paunch. See fig. 37. 



