HIPPAEOHIA. 



[ 393 ] 



HOLOPHRYA. 



elliptical, anterior end somewhat obliquely 

 truncate; cilia small, hooks slender and 

 long. Marine. Length 1-180". 



BIBL. Ehrenberg, In/us, p. 375. 



HIPPAR'CHIA, Fabr. A genus of 

 Lepidopterous Insects. 



Char. Wings more or less rounded, mid- 

 dle longitudinal 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 

 anterior pair exhibit a blackish-brown round 

 spot with a white eye or centre, is common 

 in meadows. The paler scales of the anterior 

 wings (PL 1. fig. 9) were formerly used as 

 TEST-OBJECTS. 



BIBL. Westwood, Introd. and Br. Butter- 

 flies. 



HIPPOCRE'PIA. An order of Polyzoa. 



Distinguished by the crescentic or horse- 

 shoe-shape of the tentacular disk, and the 

 presence of an epistome. Freshwater. 



Synopsis of the Families. 



CRISTATELLID.&J. Polype-mass floating. 



PLTJMATELLID^. Polype-mass rooted, 

 unjointed. 



The family Paludicellidae, containing the 

 single genus Pahidicella, is usually placed 

 here ; but it properly belongs to the Infun- 

 dibulata, as the tentacular disk is circular 

 and entire, and the epistome absent. 



See POLYZOA and URNATELLA. 



HIPPOCREPI'NA, Parker. A Lituo- 

 line Foraminifer, characterized by the horse- 

 shoe-shape of the aperture, due to the pre- 

 sence of a tongue-like process, as in Valvu- 

 lina. H. indivisa, from the Gulf of St. 

 Lawrence, is carrot-shaped. 



BIBL. Parker, in Dawson, Canad. Nat. 

 1870. 



HIPPOTH'OA, Lamx. A genus of In- 

 fundibulate Cheilostomatous Polyzoa, of the 

 family Eucratiidae (Scrupariidae). 



Distinguished by the confervoid, branch- 

 ed, creeping and adherent polyzoary, the 

 branches arising from the sides of the ellip- 

 tical cells, frequently anastomosing, and the 

 cells in one row. 



H. catennlaria. Cells contiguous, orifices 

 oval. On shells in deep water. 



H. divaricata. Cells remote, orifices round. 



BIBL. Johnston, Br. Zooph. 291 ; Gosse, 

 Mar. Zool. 12 ; Hincks, Polyzoa, 256. 



HIPPURA'RIA, Busk. A genus of 



Ctenostomatous Polyzoa. (Hincks, Poly- 

 zoa, 548.) 



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. j 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. 11. 

 fig. 18), belonging to the right rhombic 

 prismatic system, some of which bear re- 

 semblance to those of the ammonio-phos- 

 phate of magnesia, from which it is readily 

 distinguished 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. 



HIRNE'OLA, Fr. A genus of Tremel- 

 lini (Hymenomycetous Fungi), consisting of 

 gelatinous cup-shaped Fungi, horny when 

 dry, and clothed externally with short vel- 

 vety bristles. The hymenium is without 

 papillae, a character by which it is distin- 

 guished from Exidia, to which the species 

 were formerly referred. The Jews' Ear 

 (H. auricula Judce] is still sold by Herba- 

 lists as a remedy for affections of the throat, 

 the supposed virtues clearly depending on 

 the doctrine of signatures. One or two 

 species are extremely common in tropical 

 countries; and used as an article of food 

 in China. 



BIBL. Fr. Summa, 340 ; Berk, Outl. 289 



HISTOLOGICAL ANALYSIS. See 

 INTRODUCTION, p. xlii. 



HISTOLOGY, or HISTIOLOGY, is the 

 theory of the structure of animal and vege- 

 table tissues in relation to their develop- 

 ment ; but the term is often applied to the 

 microscopic structure of tissues. 



HIS'TRIO. A genus of Hypotrichous 

 Infusoria (Kent, Inf.}. 



HOLOPH'RYA, Ehr. A genus of Hoi o- 

 trichous Infusoria, of the family Enchelia. 



Char. Body covered with vibratile 

 cilia, oblong-ovate, cylindrical or globular, 



