DENDROCOMETES. 



[ 193 ] 



DEPARIA. 



when these appear enlarged, whitish, and 

 exhibit a terminal black spot. A drop of oil 

 should then be added to the secretion, and 

 the whole allowed to macerate for some 

 hours at a gentle heat. Or the secretion 

 may be digested in a mixture of alcohol and 

 aether, to dissolve the fatty matter, and then 

 treated with solution of potash. 



The secretion contains the ova, the young 

 animals, and the exuviae. When contained 

 in the follicles, the tail is directed towards 

 their orifice. 



A species of Demodex was found by Top- 

 ping in the pustules of the skin of a dog 

 affected with the "mange." This appears 

 to agree in structure with D.folliculoruni', 

 but its average size is less, amounting to 

 1-150 to 1-100" in length. It does not ap- 

 pear to constitute a distinct species, for 

 Gruby found that by inoculating the dog 

 with the human parasite, a disease resem- 

 bling, if not identical with the mange, was 

 produced. 



BIBL. Simon, Mutter's Archiv, 1842. p. 

 218; Owen, Hunterian Lectures, i. p. 251 ; 

 Gervais, Walckenaer's Apteres, iii. p. 282 ; 

 Wilson, Trans. Royal Soc. 1844. p. 305 ; 

 Tulk, Ann. Nat. Hist. 1844. xiii. p. 75 ; 

 Gruby, Ed. Month. Journ. 184?. vii. p. 333; 

 Wedl. Grundz. d. Path. Hist. p. 803. 



DENDROCOMETES, Stein. A sup- 

 posed new genus of Acinetina. The single 

 species, D. paradoxus (PI. 25. fig. 36), has 

 since been found by Stein to constitute the 

 resting stage or Acineta-form. of Sjnrochona 

 gemmipara. It represents an Acineta or 

 Actinophrys with branched arms or tentacles, 

 and is found upon the gill-plates of Gam- 

 marus pulex. 



BIBL. Stein, Siebold and Kolliker's 

 Zeitsckrift f. Wissens. Zool. 1852. iii. p.492; 

 id., Die Infus. p. 205. 



DENDROSOMA, Ehr. A genus of Infu- 

 soria, of the family Acinetina. 



Char. Consists of a thick branched pedicle, 

 fixed at its base, the branches supporting at 

 their ends numerous bodies, each resembling 

 an Actinophrys. 



D. radians. Bodies conical, thick, soft 

 and smooth, alternately branched, branches 

 incrassate and tentaculate at the ends. Size 

 1-96". Aquatic. 



BIBL. Ehrenberg, Infus. p. 316; id. Ber. 

 d. Berl Akad. 1840. p. 199. 



DENDRYPHIUM, Wallr. A genus of 

 Mucedines (Hyphomycetous Fungi), consist- 

 ing of moulds growing over dead herbaceous 

 plants, nearly related to Dactylium, but there 



Fi 



are often several spores chained together at 

 the tips of the branches ; perhaps not di- 

 stinct from Brachycladium, 

 Corda, whose species of Dac- 

 tylium (fig. 168) are brought 

 under this genus by Fries. 

 British species : 



1. D. curtum, Berk, and 

 Br. On dead stems. Ann. 

 Nat. Hist. 2 ser. vii. pi. 6. 

 fig. 9. 



2. D. laxum, Berk, and Br. 

 On dead stems. L. c. fig. 

 10. 



3. D. griseum, Berk, and 



Br. On dead steins. L. c. Demlryphium 



fig. 11. atrum. 



BIBL. Berkeley & Broome, A fertile filament 



i -i" t Tf witnseptate spores 



/. C. p. 1/6. pi. 6; Fries, upon its bran ^ hes . 



Summa Veget. 504. Magn. 200 diams. 



DENTICELLA, Ehr. See BIDDULPHIA. 



DENTICULA, Kiitz. A genus of Diato- 

 maceae. 



Char. Frustules free, single or binate, 

 prismatic and rectangular, oblong or linear 

 in front view; valves transversely striated. 

 Aquatic. 



Striae mostly coarse, not resolvable into 

 dots ; valves without a median line or no- 

 dules ; ends of the striae visible at the mar- 

 gins of the front view of the frustules ; no 

 internal septa. 



Kiitzing describes seven species. 



D. obtusa (PI. 12. fig. 25; d, front view; 

 c, valve). Valves lanceolate, obtuse at the 

 ends; length 1-330". 



The other species differ principally in size. 



BIBL. Kiitzing, Bacillar. p. 43; id. Sp. 

 Ah.-o.ll. 



DEPARIA, Hooker. A genus of Cya- 

 Fig. 169. 



Deparia prolifera. 



Sorus enclosed in the stalked indusium. 

 Magnified 25 diameters. 



thaeous Ferns, with stalked indusia shaped 

 like ancient flat goblets (fig. 169). Exotic. 



