ARTHROBOTRYUM. [ 



not in tufts, and mostly with only one 

 group of spores ; these are pear-shaped, 

 1-700" long, and have the septum below 

 the middle : it was found on damp wood, 

 fruit and earth, in a fungus-bed. 



Fig. 37. 



Fig. 38. 



Arthrobotrys superba. 



37. Fertile filament with many groups of spores. 



Magnified 200 diameters. 



38. Fertile articulation of ditto, with most of the 



spores detached from the spine-like pro- 

 cesses on which they are borne. Magnified 

 400 diameters. 



BIBL. Corda, Schimmelb. p. 43, t. 21 ; 

 Fresenius, Beitr. zur Myc., Heft i. p. 18, 

 pi. 3. figs. 1-8. 



ARTHROBO'TRYUM. Agenus of Mu- 

 cedines (Hyphomycetous Fungi), proposed 

 by Cesati, characterized by a stem composed 

 of jointed threads, bearing above large 

 jointed radiating spores, so as to form B, 

 little head. They are beautiful microscopic 

 objects. British species : 



A. atrum, B. Br. On dead nettle- 

 stems. 



A. stilboideum, Ces. On a pollard-willow. 



BIBL. Berkeley, Out. Br. Fung. p. 342 ; 

 Hedwigia, tab. 4. fig. 1. 



ARTHROCLA'DIA, Duby. A genus of 

 Sporochnaceae (Fucoid Algse). A. villosa, 

 Hucls., is a rather rare British annual sub- 

 marine species, growing in 4 to 5 fathoms 

 water ; bearing a curious pod-like nucleated 

 fruit, 



BIBL. Harvey, Brit. Mar. Alga, 2d ed. 

 p. 24, pi. 5 C. ; Phyc. Brit. t. Ixiv. ; ~Eng. 

 Bot. t. 546 ; Derbes and Solier, Ann. d. Sc. 

 Nat. 3 ser. xiv. p. 33, figs. 18-20. 



ARTHRODES'MUS, Ehr. A genus of 

 Desmidiaceae. 



Char. Cells single, compressed, constricted 



ARTOTROGUS. 



in the middle; segments entire, with a single 

 spine on each side. 



A. convergens. Segments elliptic (PL 14. 

 fig. 27) : length 1-598 to 1-539". 



A. incus, Bre"b. Segments with truncated 

 ends ; length 1-1103". 



A. minutus, Kiitz. (PL 18. fig. 9). 



A. truncatus, Ehr. 



A. subulatus. 



Other species. 



BIBL. Ralfs, Brit. Desmid. pp. 117, 200 ; 

 Kiitzing, Sp. Alg. p. 176 ; Ehreuberg, In/us. 

 p. 158 ; Rabenhorst, FL Alg. iii. p. 225. 



ARTHROGY'RA, Ehr. An obscure 

 genus of Diatomaceae. 



A. guatemaknsis (PL 51. fig. 8). Fila- 

 ment straight. 



A. semilunaris. Filament curved. Both 

 in Guatemala earth. 



BIBL. Ehrenberg, Mikrogeoloqie, pi. 33. 



ARTHROM'ITUS, Leidy. Described as 

 a genus of the Leptothriceae of Kiitzing 

 (Algae Confervoidese). Two species, A. cru- 

 tatus and A. nitidus, were found in the in- 

 testinal canal of lulm marginatus, a kind of 

 millipede. These objects appear to have 

 been imperfect forms of some filamentous 

 Fungus. See PARASITES. 



BIRL. Leidy, Proc. Ac. Philadelphia, iv. 

 p. 225, 1849 (Ann. N. If. 2nd ser. v. p. 74). 



ARTHRONE'MA, Hassall. A genus of 

 Oscillatoriacese (Confervoid Algae). 



A. cirrhosum (PL 8. fig;. 20). Filaments 

 of considerable size, striae close, evident. 

 Tufts widely spreading, filaments floating 

 in bundles. In lakes at Lismore Island. 



BIBL. Hassall, Brit. Alga, p. 238; Raben- 

 horst, Fl. Alg. ii. p. 267. 



ARTHROSI'PHON, Kiitzing. See PE- 



TALONEMA. 



ARTICULI'NA, D'Orb. Very narrow 

 varieties of Vertebralina, which commence 

 with a Milioloid (Triloculina) growth, and 

 proceed with straight moniliform chambers, 

 were separated by D'Orbigny under this 

 name. Recent and fossil. 



Articulina gibberula (PL 23. fig. 9 a b). 



BIBL. D'Orbigny, Ann. Sc. N. vii. 300 ; 

 Carpenter, Intr. For. 73. 



ARTOTRO'GUS, Mont. A genus of Se- 

 pedoniei (Hyphomycetous Fungi) contain- 

 ing one species, growing and fructifying in 

 the intercellular passages of germinating 

 potatoes. This genus is supposed by Berke- 

 ley to be founded on a secondary form of 

 fruit of some mould ; probably of Perono- 

 spora infestans. See PERONOSPORA. 



A. tiydnosporus, Mont. Berkeley, Jn. 



