P A C 



336 ] 



PAL 



ment partially immersed, attached 

 to prominent fulcra. Its place in 

 the conchological system has not 

 been determined with certainty ; 

 the P. gigus is found in the green 

 sand of Lyme Regis. Lycett. 



PACHYBI'SMA. A fossil genus of 

 thick equivalve, inequilateral bi- 

 valves, belonging to the Cardiacese 

 of Lamarck ; the figure is trans- 

 verse, oblong or cardiform, the 

 umbones are large and incurved, 

 the ligament external, placed upon 

 prominent fulcra, the hinge is 

 massive, having a large sub-conical 

 prominent tooth in each valve, and 

 a small accessory tooth in the right 

 valve. Lycett. 



PACHYDERMATOUS. Thick - skinned ; 

 belonging to the order Pachyder- 

 mata. 



PA'DDLE. The swimming apparatus 

 of the chelonian reptiles and of the 

 marine saurians, has obtained the 

 name of paddles. 



P^JCILO'PODA. (from TTOWC/XOS, and 

 TTOW, Gr. various footed.) The 

 second order of the class Crustacea ; 

 it comprises two families, Xyso- 

 plmra and Siphonostoma. 



PALA'GONITE. A mineral; an amor- 

 phous highly hydrated scapolite. 



PAL^O'LOGY. (from n-aXatos, ancient, 

 and Xo'fyos, discourse, Gr.) The 

 study of ancient things. This word 

 is commonly written paleology. 



PALEONI'SCUS. The name assigned 

 by De Blainville to a genus of 

 fossil fishes or ichthyolites, ap- 

 proximating to the sturgeons. The 

 name has also been given to a 

 genus of insects, and in order to 

 avoid confusion this latter should, 

 as applied to insects, be altered. 



PAL.&ONTO'LOGIST. (from paleontology . ) 

 One who studies, or is versed in, 

 the history of fossil plants and 

 animals. 



PALSONTO'LOGY. (from TmXruo*, an- 

 cient, wv, being, and XoV/os, dis- 

 course, Gr.) The history of fossil 

 plants and animals; that branch of 



natural history which treats of fos- 

 sil and extinct animals and plants. 



PAL^OSAU / BTJS. (from[7raXcuos, ancient, 

 and <ravpo<s t a lizard, Gr.) A genus 

 of fossil saurians, now extinct, found 

 in the magnesian limestone. 



PAL^OTHE'EITJM. } (from TraXeuo?, an- 



PAL^EOTHE'BE j cient, and Oypt'ov, 

 a wild beast, Gr.) An extinct 

 genus of fossil quadrupeds, belong- 

 ing to the order Pachydermata, 

 having six incisors in each jaw, 

 ranged in one and the same line ; 

 four canines, two in each jaw, 

 conical, and so distant as to cross 

 each other when the mouth was 

 closed ; fourteen molars in each 

 jaw, the upper of a square form, 

 with four roots and three crests on 

 the outer side, leaving between 

 them two channels ; a furrow on 

 the inner side ; their coronal nearly 

 anologous to that of the upper 

 molars of the daman and rhino- 

 ceros. The lower molars show 

 their enamelled outlines in the 

 form of a double crescent. The 

 general form of the head is 

 like that of the tapirs, the 

 nasal bones, short and slender. 

 It possessed three toes to each foot, 

 and had a short fleshy probocis. 

 "The place of the genus Palaeo- 

 therium," says Buckland, " is in- 

 termediate between the rhinoceros, 

 the horse, and the tapir. Some of 

 the discovered species were as large 

 as a rhinoceros, others were from 

 the size of a horse to that of a hare. 

 These animals probably lived and 

 died upon the margins of the then 

 existing lakes and rivers." 



PALJEOTHE'EIAN. Belonging to the 

 genus Palseotherium, as palaeo- 

 therian remains, &c. 



PAL^O'SPALAX. (from TraXatos, ancient, 

 and <T7raXa, a mole, Gr.) " An 

 extinct genus of insectivore, refer- 

 able, says Prof. Owen, to the mole 

 tribe, but as large as a hedgehog. 

 The only specimen hitherto dis- 

 covered is in the British Museum, 



