789 



menopfera, an order of insects having four 

 membranous wings, including the Wasp, 

 Bee, &c. 



HYPERBOREAN. Belonging to or inhabiting 

 the most northern regions of the earth. 



ICHTHYOLOGY. That part of zoology which 

 treats of fishes, their structure, form, and 

 classification, their habits, uses, &c. An 

 eminent writer observes, that even after 

 nations have attained to some degree of 

 knowledge and civilization, many ages 

 elapse before they push their inquiries far 

 into the subject of Ichthyology, or acquire 

 any considerable acquaintance with the in- 

 habitants of the ocean. In the unfathomed 

 depths of that turbulent and extensive ele- 

 ment, probably millions reside which are 

 secluded from human observation ; and, 

 even of the few which the industry of man 

 has, at last, drawn from their hidden abode, 

 we hardly know any thing but the external 

 figure and the names. Their food, their 

 longevity, their method of propagating 

 their kind, and the whole of their manners 

 and economy, remain still among those 

 numberless secrets of nature, which human 

 ingenuity has not hitherto been able to 

 explore." It must, however, be apparent 

 to all our readers, that true as the fore- 

 going observations may be in their general 

 application, yet, owing to the great faci- 

 lities which, of late years, have been af- 

 forded for acquiring correct information 

 on all subjects tending to the elucidation 

 of natural science aided by the zeal and 

 intelligence of many who devote their 

 lives to it that immense advances have 

 been made ; and it is with pleasure that 

 we refer to the contents of this compact 

 volume for the description of a vast num- 

 ber of the inhabitants of the watery element 

 whose forms, habits, and uses are well as- 

 certained, and whose history is scarcely less 

 interesting than is that of animals which 

 dwell on land, or which wing their way 

 through the regions of aerial space. [See 

 FISH.] 



ICHTHYOPHAGOUS. Feeding or subsisting on 

 fish. 



IDIOPATHIC. A term indicative of a disease 

 peculiar to a part of the body, and not 

 arising from any preceding disease : op- 

 posed to sympathetic, when it is the con- 

 sequence of some other disorder. 



IMAGO. The last and adult state of insect 

 life, i. e. the third or perfect state of insects, 

 when they appear in their proper shapes 

 and colours, and undergo no more trans- 

 formations. 



IMBIBITIOK. The act of drinking in or 

 absorbing. 



IMBRICATED. Lapping over each other, like 

 the tiles of a house, or as the scales of some 

 fishes and insects. 



IMMARGINATE. Being without a margin. 



IMMISCIBLE. Not capable of being mixed. 



IMMATURE. That has not acquired its per- 

 fect form or full colour. 



IMPENNATES. Swimming birds having short 

 wings, as the Penguin. 



IMPERMEABLE. Not to be passed through 

 the pores by a fluid. 



IMPOROUS. Close or compact in texture ; 

 perfectly solid. 



IMPOTENT. Deficient in natural power, 

 animal or intellectual. 



IMPREGNATED. Rendered prolific or fruit- 

 ful. 



INARTICULATED. Not jointed. 



INAURATE. When striae or other impressed 

 parts have a metallic splendour. 



INCISED. Cut into equal marginal segments. 



INCISORS. The fore- teeth; the teeth used 

 for cutting or separating the food ; an im- 

 portant generic character in zoological 

 science. 



INCISURE. A deep incision between the seg- 

 ments of an insect, when they recede from 

 each other. 



INCONSPICUOUS. Not to be perceived by the 

 sight. 



INCUASSATE. Disproportionably thick in 

 any part. 



INCRUENTAL. Not attended with blood. 



INCUBATION. The act of sitting on eggs for 

 the purpose of hatching young. 



INCUMBENT. Lying over another. 



INCURVATED. Turned from a rectilinear 

 direction. 



INCUEVED. Turned inwards or bent forwards. 

 The apex of a shell is said to be incurved 

 when it is bent inwards, but not sufficiently 

 so to be described as spiral. 



INDECIDUOUS. Not falling off; lasting. 



INDENTED. Exactly the reverse of dentated; 

 meaning a series of small cavities, such 

 as might be formed by the entrance of 

 teeth. 



INDIGENOUS. Produced naturally in a 

 country ; not exotic. 



INDIVIDUALISE. To distinguish the peculiar 

 properties of one from another : the word 

 individual and its derivatives are, however, 

 rarely applied to any but human beings. 



INEQUILATERAL. When the anterior and 

 posterior sides of a bivalve shell are unequal 

 in length. 



INEQUIVALVE. When one valve is more 

 convex than another, or dissimilar in other 

 respects, as in the common oyster. 



INFECUNDITY. Unfruitfulness ; barrenness. 



INFERIOR VALVE (applied only to attached 

 bivalves). The valve that is attached to 

 submarine bodies. 



INFLECTED. Bent inwards. 



INFLEXED. When the head of an insect forms 

 inwards an acute angle with the trunk. 



IJTFUNDIBULIFORM. Funnel-shaped. Whose 

 horizontal sections are circular, at first 

 equal and then progressively larger and 

 larger. 



INFUSCATE. To darken. When a colour is 

 darkened by the superinduction of a brown- 

 ish shade or cloud. 



INGUINAL. Pertaining to the groin. 



INNOCUOUS. Harmless ; producing no ill 

 effect. This word is applied only to things, 

 not to persons ; as, there are some poisons 

 used as medicines which, if taken in small 

 quantities, prove not only innocuous but 

 beneficial. 



INOCULAR. When the antennae are inserted 

 in the canthus of the eyes. 



INODOROUS. Wanting scent; having no 

 smell. 



