PERACANTHA. 



f 586 ] 



PERIGLISHRUS. 



may be detected by the starch-granules 

 those existing in pepper itself being exceed- 

 ingly minute particles ; the same remark 

 applies to rice and pea-flour, &c. Exces- 

 sive quantities of the husk-tissue in black 

 pepper denote that the refuse of the decor- 

 ticated white peppers has been added. (See 

 also CAYENNE.) 



BIBL. Pereira, Mat. Medico, ; Hassall, 

 Food and its Adulterations, 42. 



PERACANTHA, Baird. A genus of 

 Entomostraca, of the order Cladocera, and 

 family Lynceidae. 



Char. Side view of shell oval, the lower 

 and posterior portion with an acute projec- 

 tion directed backwards and upwards, and, 

 as well as the upper extremity of the ante- 

 rior margin, beset with strong hooked 

 spines ; beak sharp, curved downwards. 



P. truncata (PI. 19. fig. 31). Superior an- 

 tennae conical j inferior short, the anterior 

 branch with five setae, one from first, one 

 from second, and three from last joint ; pos- 

 terior branch with three setae from the last 

 joint only ; intestine convoluted, with one 

 turn and a half ; ova two ; freshwater. 



BIBL. Baird, Brit. Entom. 136. 



PERANE'MA, Duj. A genus of Flagel- 

 late Infusoria, family Euglenia. 



Char. Form variable, globular, or inflated 

 posteriorly and narrowed in front, where it 

 becomes prolonged into a long flagelli- 

 form filament; movement slow, uniform, 

 forwards. 



P. ylobulosa (PI. 31. fig. 59). Body almost 

 globular, more or less drawn out anteriorly, 

 with oblique wrinkles on the surface ; 

 freshwater; length 1-1400". 



BIBL. Dujard. Inf. 353 ; Pritchard, Inf. 

 545. 



PERANE'MA, Don = SpEUEROPTEitis. 



PERFORATA, Carpenter. The Di- 

 vision of Foraminifera that possess a vitre- 

 ous or hyaline shell perforated by tubular 

 openings for the exit of pseudopodia. 



BIBL. Carpenter, Introd. Foram. 149. 



PERICH^E'NA, Fr. A genus of Myxo- 

 mycetes, consisting of little rounded mem- 

 branous sacs of brownish or yellowish colour, 

 generally splitting all round (transversely), 

 and discharging yellow spores and (few) 

 free and elastic filaments. The commonest 

 (P. populina), yellowish and about as large 

 as a mustard-seed, occurs on fallen poplar 

 trees ; two others occur in fir-plantations. 



BIBL. Berkeley, Hook. Br. Fl. ii. pt. 2. 

 321; Fries, Syst. Myc. 190; Sum. Veget. 

 459; Greville, Crypt. Flora, 252. 



PERICO'NIA, Tode. A genus of De- 

 matiei (Hyphomycetous Fungi), character- 

 ized by a stem composed of fasciculate com- 

 pacted threads. Head globose ; spores fixed 

 on the free apices of the threads. It is 

 analogous to Pachnocybe. Tulasne states 

 that it is merely a conidiiferous form of 

 some Sphceria, Two species occur in this 

 country. 



P. glaucocephala, Cd. ; on decayed linen. 



P. calicioides, B. ; on dead herbaceous 

 stems. 



BIBL. Fries, Summa Vey. 168; Berk. 

 & Broome, Ann. N. H. 2. v. 165 ; Tulasne, 

 Ann. Sc. Nat. 4. v. 109; Cooke, Handb. 

 565. 



PERIDERM. See BARK. 



PERIDER'MIUM, Lk. A genus of 

 Uredinei (Hypodermous Fungi), distin- 

 guished from ^ECIDIUM by the sac-like 

 perithecium bursting irregularly, as if by a 

 circumscissile dehiscence. The' type of this 

 genus is P. (jEcid.} Pint, found on the 

 leaves and bark of Scotch Firs. The spores 

 are covered with very numerous small 

 tubercles. See UREDINEI. 



BIBL. Berk. Br. Fl. ii. pt. 2. 374; Tu- 

 lasne, Ann. Sc. Nat. 4 se*r. ii. 176, pi. 10 ; 

 De Bary, Brandpilze, 1853, 72. 



PERIDINI'NA. An Order of Cilio- 

 flagellate Infusoria (see p. 422). 



PERIDIN'IUM. A genus of Peridinina 

 (Cilio-flagellate Infusoria). 



Char. Body with a transverse groove, the 

 two portions of the facetted lorica nearly 

 equal. 



Those species with a horn-like process, 

 are sometimes separated as Ceratium. 



P.fuscum (PL 31. fig. 11). Brown, not 

 luminous, carapace ovate, slightly com- 

 pressed, smooth, acute in front, rounded 

 behind; freshwater; 1. 1-430 to 1-290". 



P. (G) tripos (PI. 31. fig. 12). Yellowish, 

 splendidly phosphorescent ; carapace urceo- 

 late, broadly concave, mouth with three 

 horns, two very long, frontal, and recurved, 

 the third posterior and straight ; marine ; 

 length 1-140". 



Several other species. See GLENODI- 

 NIUM. 



BIBL. Ehr. Inf. 262; Duj. Inf. 374; 

 Allinan, Micr. Jn. iii. 24 ; Clap, et Lach. 

 Etudes, 403 ; Clark, Ann. N. H. 1865, xvi. 

 270 ; Kent, Inf. 447. 



PERIGLIS'CHRUS,Koch. SeePTEROP- 



TUS. 



The species adhere by the margin of the 

 body all round. 



