112 CHECK LIST (Jb THE 



Hyomandibular. A bone by which the posterior end of the suspensorium 

 is articulated with the skull ; the supporting elenient of the sus- 

 pensorium, the mandible, the hyoid apparatus, and the opercular 

 apparatus. 



Hypercoracoid. The upper of the two bones attached to the clavicle indi- 

 rectly bearing the pectoral fin. 



Hypleural. The modified last vertebra supporting the caudal fin. 



Hypobranchials. Bones of the branchial arches below the ceratobranch- 

 ials. 



Hypocoracoid. The lower of the two bones attached to the two clavicles 

 behind. 



Hypognathous. Having the lower mandible longer than the upper, as in 

 the Black Skimmer. 



Hypophyals. Small bones, usually four, by which the respective sides of 

 the hyoid apparatus are joined. 



I. 



Imbricate. Overlapping, like shingles on a roof. 



Imperforate. Not pierced through. 



Inarticulate. Not jointed. 



Incisors. The front, or cutting teeth. 



Infraoral. Below the mouth. 



Interferaoral membrane. The membrane connecting the posterior limbs 



of a bat. 

 Interhaemal spines. Elements supporting the anal fin. 

 Interhaemals. Bones to which anal rays are attached in fishes. 

 Interhyal. Upper hyoid bone attached to hyomandibular. 

 Intermaxillaries. The premaxillaries ; the bones forming the middle of 



the front part of the upper jaw in fishes. 

 Intermusculars. Synonym of epipleurals. 

 Internasals. Plates on the forehead of the snake on the line connecting 



the two nostrils. 

 Interneurals. Bones to which the dorsal rays are attached in fishes. 

 Interopercle. Membrane bone between the preopercle and the branchio- 



stegals. 

 Interorbital. Space between the eyes. 

 Interscapular. Between the shoulders. 

 Interspinals. Bones to which fin-rays are attached (in fishes) inserted 



between neural spines above and haemal spines below. 

 fsocercal (tail). Last vertebras progressively smaller and ending in median 



line of caudal fin as in the Cod-fish. 

 Isthmus. The narrow unperforated floor of the mouth, between the gill 



openings in fishes. 



