HIMANTIDTUM. 



[ 324 J 



HOLOPHRYA. 



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 nume- 

 rous pores leading to immersed conceptacles 

 resembling those of Fucus, containing either 

 parietal spore-sacs or antheridia, 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 sper- 

 matozoids of flattened, ovoid or spherical 

 forms, with an orange granule and two cilia, 

 like those of Pycnophycus and Halidrys. 



BIBL. Harvey, Brit. Mar. Alg. p. 20. 

 pi. 2 B ; Thuret, Ann. des Sc. nat. 3 ser. 

 xvi. p. 54 et seq. ; Greville, Alg. Brit. pi. 3; 

 Engl. Sot. pi. 569. 



HIMANTIDIUM, Ehr. A genus of Dia- 

 tomaceae. 



Char. Frustules resembling those of Eu- 

 notia, connected by their sides into a fila- 

 ment. Aquatic. 



Kiitzing describes thirteen species, some 

 of which are fossil. 



H. pectinate (Fragilaria pect. Ralfs) (PL 

 12. fig. 36). Frustules in side view constricted 

 at the curved and rounded ends ; one side 

 slightly raised and flat, the other slightly 

 excavated or flat; striae evident; length 

 1-180". 



/3. Convex margin of side view undulate 

 or with two indentations (fig. 36, b}. 



Mr. Ralfs remarks a difference of form 

 between the newly-forming and the parent 

 frustules, the lateral margins of the former 

 in the front view being rounded (fig. 36, c). 



H. arcus. Frustules rectangular in front 

 view; valves linear-arcuate, ends rounded, 

 subrecurved; striae evident; length 1-300 

 to 1-132". 



H. monodon (Eunotia mon. Ralfs). Frus- 

 tules in side view subarcuate, convex on one 

 side, concave on the other, ends broadly 

 rounded ; striae evident ; length ? 



BIBL. Ehrenberg, Ber. d. Berl. Akad. 

 1840 ; Kiitzing, Bacill. p. 36, Sp. Alg. p. 8 ; 

 Ralfs, Ann. Nat. Hist. xii. p. 107, xiii. p. 459. 



HIMANTOPHORUS, Fabricius. A 

 genus 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. 24. fig. 18, under view; 

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

 elliptical, anterior end somewhat obliquely 

 truncate ; cilia small, hooks slender and long. 

 Marine. Length 1-180". 



BIBL. Ehrenberg, Infus. p. 375. 



HIPPARCHIA, Fabr. A genus of Lepi- 

 dopterous Insects. 



Char. Wings more or less rounded, 

 middlelongitudinal nerve of fore- wings giving 

 off posteriorly four nerves ; antennae with an 

 elongate, compressed and curved club ; head 

 small. 



H. Janira, the meadow-brown butterfly, 

 in which the wings are brown, and the ante- 

 rior pair exhibit a blackish-brown round 

 spot with a white eye or centre, is common 

 in meadows. The scales (PI. 1. fig. 9) are 

 sometimes used as TEST-OBJECTS. 



BIBL. West wood, Introduction, tyc., and 

 British Butterflies. 



HIPPURIC ACID. This acid occurs in 

 small quantity in human urine, especially 

 after a vegetable diet ; more largely in that 

 of the horse and other herbivora, as the ox, 

 the goat, the sheep, the hare, &c. ; also in 

 that of some reptiles. 



It is readily soluble in boiling water and 

 alcohol ; less so in cold water and in ether. 



It crystallizes in prisms or needles (PI. 7 ' 

 fig. 18), belonging to the right rhombic 

 prismatic system, some of which bear resem- 

 blance to those of the ammonio-phosphate 

 of magnesia, from which it is readily distin- 

 guished by its solubility in potash or hot 

 water. It" is sometimes obtained under the 

 same circumstances as benzoic acid, from 

 which it differs in its greater solubility in 

 ether, and in the thickness and solidity of 

 its prisms, those of benzoic acid being thin 

 and plate-like. Its crystals are beautifully 

 analytic ; which property is deficient in those 

 of benzoic acid. 



It may best be procured from cow's urine, 

 by boiling with slaked lime for some time, 

 filtering and supersaturating with muriatic 

 acid; and it may be purified by repeating the 

 process and using animal charcoal. 



BIBL. See CHEMISTRY. 



HISTOLOGICAL ANALYSIS. See IN- 

 TRODUCTION, p. xxxvi. 



HISTOLOGY or HISTIOLOGY, is the 

 doctrine of the structure of animal and vege- 

 table tissues in relation to their development. 



HOLOPHRYA, Ehr. A genus of Infu- 

 soria, of the family Enchelia. 



