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It is nearly allied to A. Flos-aeris RCHB. F., A. Mainguyi Schltr., 

 and A. Hookeriana Rchb. f., vvhich are often cultivaied in Java. Tlit-se 

 four species may be distinguished as follows. 



Arac/mis Flos-aeris Rchb. f. Flowers c. 8.5 cm. across, greeiiisli yellow 

 witli dark brovvii blotches, stroiigly sceiited of musk. Lip subcubic in 

 outline, ihe back and lower side in a right angle, the callus depressed 

 nearly as long as the lip, tips of the side lobes recurved. Leaves sniooth. 



Arachnis Vanmullemii }.].S>. Flowers c. 7.5 cm. across, paleyellowish 

 with chestnut brown blotches, sweetly scented. Lip subcubic in outline, 

 the back and lower side in a right angle, the callus conic, trilatéral, 

 shorter than the midlobe, lips of side lobes hardly recurved. Leaves 

 dentate at the base. 



Arachnis Mainguyi Schltr. Flowers c. 6.5 cm. across, whitish with 

 purple blothes, scentless. The back and lower side of the lip in an obtuse 

 angle, hence the midlobe manifestly S4irpassing the side lobes, the callus 

 conic, trilatéral, laterally compressed, equalling the midlobe, tips of side 

 lobes manifestly recurved. Leaves smooth. 



Arachnis Hookeriana Rchb. f. Flowers c. 5.25 cm. across, pale yellow 

 with a few pale purplish spots on the sepals, scentless. The back and 

 lower side of the lip in a right angle, midlobe manifestly surpassing the 

 side lobes and column, the callus only forming an obtuse angle on the 

 lower surface of the midlobe, side lobes somewhat recurved at the apex. 

 Leaves dentate at the base. 



M a 1 1 e 1 a b a 1 i e n s i s J. J. S. n. sp. 



Caulis brevis, patens, sectione transversa ellipticus, ad c. 3.5 cm. iongus, 

 internodiis c. 0.6 cm. longis. Folia c. 3—5, patentissima, basi semitorta, 

 oblonga ad lanceolata. apice saepe breviter contracta, obliqua, lateribus 

 saepe semiobtusis denticulatisque, basi obtusa, praesertim margine postico 

 undulata, convexa cum canalicula longitudinali, costa subtus obtuse promi- 

 nente, carnoso-coriacea, opaca, sordide viridia, valde violaceo-suffusa et 

 punctata, c. 6.5 — 9.5 cm. longa, 2.2—4 cm. lata; vaginae tubulosae, latera- 

 liter compressae, sectione transversa ellipticae, colore folii, internodia vix 

 superantes, c. 0.5—0.8 cm. latae. inflorescentiae vaginam dorso ad basin 

 perforantes, deorsum spectantes, densius multiflorae, c. 2.4 cm. diam., pe- 

 dunculo purpureo, pallide viridi-maculato, c. 1 — 1.3 cm. longo, vaginulis 

 c. 2 brevibus donato, rachide angulata, lateribus concava, colore pedunculi, 

 c, 2.5 — 7.5 cm. longa. Bracteae reflexae, triangulae, acutae, marginibus in- 

 curvis concavae, purpureae, c. 0.2 — 0.35 cm. longae. Flores parvi, quaqua- 

 versi, patentissimi, c. 0.64 cm. lati, 0.875 ci", longi, sepalis petalisque p:i- 

 tentissimis, praesertim sepalis incurvis, carnosulis, ochraceis. Sepalum dor- 

 sale cum ovario angulum obtusum faciens, valde incurvum, valde concavum, 

 oblongo-ovale, obtusum, basi contractum, obsolète purpureo-suffusum, c. 0.5 

 cm. longum, 0.23 cm. latum. Sepala lateralia defiexa, angulum acutum 

 facientia, incurva, valde oblique spatluilato-elliptica, marginibus proximis 

 roîundato-dilatata, marginibus pcsticis subiecta, obtusa, concava, dimidio 



