AMPIIISTOMA. 



AMYLOBACTER. 



other they are packed in around the umbo 

 among the chambers, to which they are at- 

 tached by very narrow necks. The aperture 

 also lies somewhat on this side of the me- 

 dian plane. Living abundantly in some 

 parts of the tropical seas ; and found fossil 

 in some Tertiary strata younger than those 

 rich in Nummulites. Recent, South Seas ; 

 fossil, Middle Tertiary, Australia, Europe. 



Amphistegina Haueri (PI. 24. fig. 38). 



BIBL. D'Orbigny, For. Foss. Vien. ; Car- 

 penter, Foram. p. 241. 



AMPHIS'TOMA (Holostomum, Diplo- 

 discus). A genus of Entozoa of the family 

 Trematoda. 



Char. Body soft, oval, cylindrical or co- 

 nical ; intestine 2-branched ; two pores, one 

 anterior, the other posterior forming a large 

 sucker. 



The species are numerous, most common 

 in birds, but sometimes occur in mammalia, 

 reptiles, and fishes ; generally inhabiting the 

 alimentary canal ; length from 1-10 to 4-5 

 of an inch. 



A. hominis, in man (India) ; near the ileo- 

 colic valve; red; " long. 



BIBL. Dujardin, Helm. p. 327; Diesing, 

 Syst. Helm. ; Proc. Asiat. Soc. 1876 j Cob- 

 bold, Paras. 1879, p. 37 (fig.)- 



AMPHITET'RAS, Ehr. A genus of 

 Diatomacese (Cohort Anguliferae). 



Char. Side view of the f rustules rectangu- 

 lar, the angles sometimes produced ; valves 

 covered with depressions, which are readily 

 seen under a low power. 



This genus approaches Isthmia and Bid- 

 dulphia, from which it differs in its rectan- 

 gular and not compressed figure. 



A. antediluviana (PI. 16. fig. 9) ; o, frus- 

 tules united ; b, side view ; c, front view ; 

 d, perspective view. Lateral surfaces of 

 the frustules with concentric radiating de- 

 pressions, their sides concave. British ; 

 marine. 



A. adriatica. Depressions concentric 

 and radiating ; angles of the frustules ob- 

 tuse ; lateral surfaces of frustules with 

 straight sides ; Adriatic sea. 



A. parallela. Depressions parallel; in 

 Greek marl. 



10 other species. 



BIBL. Kutzing, Badll. p. 135 j Sp. Alg. 

 p. 133 ; Ehrenberg, Abh. d. Berl. Ak. 1839, 

 pp.122, 144; Greville, Mic. Trans. 1865, 

 p. 105, 1866, p. 9 ; Rabenhorst, Flor. Alg. 

 i. p. 318. 



AM'PHITHRIX, Ktz. A genus of Ri- 

 vulariaceous Algae j consisting of erect, 



tufted, flagelliform filaments ; with crowded 

 fine articulated fibrils at the base. On wet 

 rocks, the sides of aquaria, &c. ; fr. water. 



A. papillosa (PI. 3. fig. 4). 



BIBL. Rabenhorst, Alg. ii. p. 229. 



AMPHIZONEL'LA, Greeff. A genus of 

 Rhizopoda=-/4w&a with a very delicate 

 shell. 



3 species ; fresh water. 



BIBL. Greeff; Arch. f. mik. An. 1866, ii. 

 p. 323 ; Bronn, Klaus, pi. 1. fig. 7. 



AM'PIIORA, Ehr. A genus of Diato- 

 macese (Cohort Naviculese). 



Char. Frustules solitary, free or adherent; 

 valves with a nodule or a stauros at the 

 middle of the margin on the inner side. 



The nodules exist on the flat side of the 

 frustules ; the frustules are plano-convex ; 

 PI. 16. fig. 10 a represents a transverse sec- 

 tion ; the side view of the frustules can only 

 be seen when these are made to roll over 

 by sliding the glass cover upon the slide 

 with the mounted needle. (INTRODUCTION, 

 p. xxiii.) 



The valves are furnished with transverse 

 striae, resolvable into dots, but in some spe- 

 cies these are excessively minute. 



The species are both marine and aquatic. 



A. ovalis, K. Aquatic ; frustules turgid, 

 oval, ends rounded or truncate ; length 

 1-400"; common. (PI. 16. fig. 10, front 

 view; 10 a represents a transverse section.) 



A. minutissima, S. Aquatic, adherent to 

 other Diatomacese ; valves with a stauros ; 

 length 1-1200". 



A. costata, S. Marine ; ends beaked j 

 valves longitudinally ribbed ; length 1-500". 



A. membranacea, S. (PI. 16. fig. 11); 

 brackish water. 



Rabenhorst describes 54 European and 

 22 other species. 



BIBL. Kiitz. Bacill. p. 107 ; Sp. Alg. p. 

 93; Smith, Brit. Diat. i. p. 19 ; Rabenhorst, 

 Flor. Alg. i. p. 86. 



AMPHOROPH'ORA, Buckt. A genus 

 of Aphidse. 



A. ampullata is very large, green ; eyes 

 red, with very long antennae fixed on the 

 frontal tubercles ; cornicles large, dilated in 

 the middle, with black trumpet-shaped 

 orifices. On Cystopteris montana. 



BIBL. Buckton, Aphides (Ray Soc.}. 

 1879, i. p. 187. 



AMYLOBAC'TER, Tre*cul. The orga- 

 nisms to which this name has been applied 

 are obtained by macerating the stems of 

 plants of various families in water. They 

 are round, or oval, often bacillar and capi- 



