GAMASUS. 



[ 348 ] 



GASTEROMYCETES. 



body with usually two dorsal plates; an- 

 terior legs generally longest, second pair 

 sometimes incrassate ; no eyes. On insects, 

 &c. (PI. 6. fig. 26). 



Pteroptus. Body depressed; last joint 

 of palpi longest; legs stout, with short 

 joints. On bats (PL 6. fig. 39). 



Uropoda. Body depressed, with a round 

 dorsal plate, and a deciduous funnel-shaped 

 anal peduncle, serving to fix the body. On 

 beetles, mosses, &c. (PI. 6. fig. 25). 



Halarachne. Body elongate, with a dor- 

 sal and ventral plate ; labium bifid. In the 

 nostrils of a seal (Halichcerus). 



See also ARGAS and CARIS. 



BIBL. Gervais, Walckenaer's Apt. iii. 

 215 ; Duges, Ann. Sc. Nat. 2 ser. 24 ; Koch, 

 Deutsch. Crustac. and Uebersicht ; Murray, 

 EC. Entom. 157; Megnin, Paras. 113; 

 Kramer, Wiegm. Arch. 1876, i. 28; Tr. 

 Mic. Soc. 1880, 177. 



GAM'ASUS, Latr. A genus of Arach- 

 nida, of the order Acarina, and family GA- 

 MASEA. 



Species numerous ; mostly parasitic upon 

 insects ; some found upon the ground ; 

 others on the higher animals. 



G. coleoptratorum (PL 6. fig. 26). Found 

 upon dung-beetles (Geotrupes &c.). An- 

 terior coxse attached at a little distance from 

 those of the second pair ; tarsi (fig. 26 a) 

 with two claws and an elegant caruncle ; 

 palpi of moderate length ; mandibles ter- 

 minated by a curved hook ; fawn-coloured. 



G. marginatus. Body broader behind ; 

 darker. Found in the human brain; also 

 on a fly, and on beetles. 



G. muscarum. On the house-fly. 



G. auris. In aural meatus of ox. 



Other species. 



BIBL. That of the family ; Leidy, Proc. 

 Acad. Phil. 1872 (Ann. N. H. 1873, xi. 

 79) ; Murray, EC. Ent. 158. 



GAM'MARUS, Latr. A genus of Crus- 

 tacea, of the order Amphipoda, and family 

 Gammarina. 



The searcher for the freshwater Diatoma- 

 cese will surely meet with Gammarus pidex 

 (PI. 18. fig. 22), the freshwater shrimp, in 

 muddy brooks and streams. It attains a 

 length of about 1-2", and moves its curved 

 body through the water by means of its 

 caudal appendages, frequently lying on its 

 back or side during the process. Gervais 

 distinguishes G. flumatilis from G. pulex, 

 by the former having a dorsal spine at each 

 abdominal joint, whilst in the latter this is 

 absent. 



There are twenty-three species of Gam- 

 mai*us, many of them marine. Talitrus sal- 

 tator, the sand-hopper, found burrowing in 

 and hopping upon the sand of the sea-shore, 

 also belongs to the family Gammarina. 



BIBL. Desmarest, Consid. gen. Crust. ; 

 M.-Edwards, Crustac. iii. ; Gervais, Ann. 

 Sc. Nat. 1835, iv. ; Westwood, Phil. Tr. 

 1835 ; Bate and Westwood, Ann. N. H. 

 1857, xix. 135 ; Rentsh, Gamm. orn. 1861. 



GANGLION-GLOBULES, or NERVE- 

 CELLS. See NERVES. 



GAPES. A disease occurring in poultry, 

 arising from entozoa (Sclerostoma and 

 Syngamus) in the air-passages. 



GARVEI'A, T. S. Wright. A genus of 

 Hydroid Polypes, fam. Atractylidse. 



G. natans. Body red, tentacles yellow ; 

 marine; height 1" On rocks and sea-weeds. 



BIBL. Hincks, Brit. Zooph. 101. 



GASTEROMYCETES. A tribe of 

 Basidiomycetous Fungi, characterized by 

 the production of their free spores upon 

 basidia seated on a sporiferous structure 

 forming convolutions in the interior of an 

 excavated fruit, which ultimately bursts to 

 allow the sporiferous structure to expand 

 and scatter its spores. The fruit of the 

 Gasteromycetes is ordinarily a globular, 

 elliptical, or shapeless mass, varying in size 

 from microscopic minuteness to the dimen- 

 sions of large balls, often stalked, arising 

 'from an inconspicuous flocculent mycelium. 

 This external body consists of a leathery or 

 membranous, simple or double sac (pe- 

 ridium}, which bursts in various ways at 

 maturity. When examined young, these 

 Fungi appear solid ; but as they advance, 

 various structures become gradually marked 

 out in their interior, and appear more and 

 more distinct until mature. 



In the Nidulariacei little conceptacles are 

 developed in the interior of the sac-like pe- 

 ridium ; and when the latter is mature, it 

 opens like a cup or vase at its summit, ex- 

 hibiting the conceptacles w'ithin, lying like 

 eggs in a nest. These conceptacles are 

 hollow, and lined with basidia bearing free 

 spores. 



The Trichogastres exhibit in most cases 

 the appearance of a leather ball, arising 

 from an inconspicuous flocculent mycelium ; 

 but in Broomeia the peridia are imbedded 

 in large numbers in a common fleshy matrix. 

 The internal structure differs to a consider- 

 able extent in its earlier stages. The peri- 

 dium is either single or double, the outer 

 being often quite free, and becoming everted 



