HETEROTRICHUS. 



[ 392 ] 



HDIANTOPHORUS. 



BIBL. Reuss, Sitz. Ak. Wien, Hi. ; Parker 

 and Jones, Ann. N. H. ser. 4. ix. 21)8. 



HETEROT'RICHUS, Donnadieu. A 

 genus of Acarina, fani. Garnasea. 



H. inaquarmatus. Hairs jointed, longer 

 than the body. 



BIBL. Donnadieu, Jn. de TAnat. 1876 

 (Mn. Mic. Jn. 1877, xvii. 283, fig.). 



HEWAR/DIA, Hook.=Adiantum, pt. 



HEXAM'ITA, Duj. A genus of Flagel- 

 late Infusoria. 



Char. Body oblong, rounded in front, 

 constricted and bifid or indented behind; 

 four flagelliform filaments arising separately 

 from the anterior margin, the two posterior 

 lobes being prolonged into flexuous fila- 

 ments. 



If. nodidosa (PI. 31. fig. 20). Oblong, 

 with three or four longitudinal rows of no- 

 dules ; motion vacillating ; length 1-1800". 

 In decomposing marsh-water. 



H. inflata ; in decomposing infusions. 



H. intestinalis. Fusiform, prolonged into 

 a bifid tail j length 1-2100' '. In the intes- 

 tines and peritoneal cavity of the Batrachia 

 and Tritons. 



BIBL. Dujardin, Infos. 296 ; Kent, Inf. 

 318. 



HILDENBRANDTIA, Zanardini. A 

 genus of Nulliporous Corallinaceae (Flori- 

 deous Algae), containing one British species, 

 H. sanguined, Kiitz. : common, in the form 

 of a bright or dark red membranous crust, 

 at first circular, afterwards spreading irre- 

 gularly over smooth stones and pebbles. 

 Frond about 1-20" thick in the middle, 

 thinner toward the edges, and composed of 

 minute globose cells, partly vertical, partly 

 horizontal ; it is not stony. ' It has immersed 

 conceptacles, pierced by a pore (fig. 250, 

 p. 327), containing tetraspores and para- 



le species occurs in alpine streams. 



BIBL. Harvey, Mar. Alg. 110, pi. 14 C ; 

 Phyc. Brit. pi. 250 ; Kiitz. Phyc. Gen. pi. 

 78. fig. 5; Rabenhorst, Fl. Alg. iii. 408. 



HI'LUM. This name is applied to the 

 surface of attachment of the funiculus of 

 seeds, which is seen as a kind of scar, more 

 or less distinct. Sometimes it coincides 

 with the chalaza or organic base of the 

 seed, sometimes, where a raphe exists, it is 

 near the rnicropyle. (See OVULE.) 



HIMANTHA'LIA, Lyngbye. A genus 

 of Fucaceae (Fucoid Algae), remarkable for 

 the peculiar forms of the frond and recep- 

 tacle, the latter consisting of a repeatedly 

 forked strap-shaped cord from 2 to 10' long, 



springing from the top-shaped frond, which 

 is about an inch high. The dark olive-green 

 thong-like H. lorea is common on rocky 

 sea-shores. The receptacle is pierced by 

 numerous pores leading to immersed con- 

 ceptacles resembling those of Fucus, con- 

 taining either parietal spore-sacs or antheri- 

 dia, the plants being dioecious. The centre 

 of the receptacle is filled with mucous 

 matter traversed by jointed filaments. The 

 antheridial sacs of Himanthalia are double, 

 and contain spermatozoids of flattened ovoid 

 or spherical forms, with an orange granule 

 and two cilia, like those of Pycnophycus 

 and Halidrys. 



BIBL. Harvey, Mar. Alg. 20, pi. 2 B ; 

 Thuret, Ann. Sc. Nat. 3 se"r. xvi. 54 ; Gre- 

 ville, Alg. Brit. pi. 3 ; Engl. Bot. pi. 569. 



HIMANTID'IUM, Ehr. A genus of 

 Diatomaceae, cohort Eunotieae. 



Char. Frustules resembling those of Eu- 

 notia, connected by their sides into a fila- 

 ment; striae transverse, parallel. Fresh- 

 water. 



Kutzing describes thirteen species, some 

 of which are fossil ; Smith admits eight 

 British species, one doubtful. 



H. pectinale (Fragilaria pect., Ralfs) (PI. 

 16. fig. 36). Frustules in side view nar- 

 rowed at the curved and rounded ends ; 

 one side slightly raised and flat, the other 

 slightlv excavated or flat ; striae evident ; 

 length 1-180*. 



/3. Convex margin undulate or with two 

 indentations (fig. 36 b) = H. undttlatum, Sm. 

 Ralfs remarks a difference of form between 

 the newly-forming and the parent frustules, 

 the lateral margins of the former in front 

 view being rounded (fig. 36 c). 



H. arcus. Fr. rectangular ; valves linear- 

 arcuate, ends rounded, subrecurved ; striaa 

 evident; length 1-300 to 1-132". 



BIBL. Ehrenberg, Berl. Ber. 1840 ; Kut- 

 zing, Bacill. 36 ; Sp. Alg. 8 ; Ralfs, Ann. 

 N. H. xii. 107, xiii. 459 ; Smith, Br. Diat. 

 ii. 10. 



HIMANTOPH'ORUS,Fabricius. A ge- 

 nus of Infusoria, of the family Euplota. 



Char. Head not distinct from the body ; 

 hooks numerous ; neither styles nor teeth 

 present. 



Long curved hooks, almost in pairs, form 

 a broad band on the ventral surface, and are 

 the organs of locomotion ; also a row of cilia 

 extending from the mouth a considerable 

 distance backwards. 



H. Charon (PI. 31. fig. 18, under view ; 

 fig. 19, side view). Body hyaline, plane, 



