MOUPHOLOGY OF TELEOSTEAN HEAD SKKLETON. 585 



opening between the cavum cranii and auditory capsule 

 (pp. 562—568). 



A quadrate cartilage supporting a lower moveable jaw, 

 formed by the union of two cartilages in the middle line^ 

 and bearing dorsally two, possibly three processes ; an 

 anterior one, parallel to its fellow, and not united with 

 it, but with the ethmoid plate, so tliat a moveable upper 

 jaw did not exist; a middle one articulating with the 

 trabeculge, in the region lying between the optic and 

 trigeminal nerves ; a posterior one articulating with the 

 auditory capsule (pp. 568 — 573). 



A branchial apparatus consisting of at least five arches, 

 already segmented into four parts. 



Balfour's term Prolognathostomata (81, p. 271) would be 

 sufficiently expressive of such a type. 



8. The manner of mandibular suspension in Teleosts is 

 insufficiently described by the term Hyostylic (pp. 569, 670). 



9. The Lophobranchii and Hemibranchii should no longer 

 be kept in separate orders, for they together constitute a 

 natural group, which may be designated the Thoracostei 

 (pp. 575—579). 



10. The Scomberesoces, through the Gasterosteoidei, 

 approach more closely to the Thoracostei than do any other 

 living Physoclisti, and seem to form with them a compact series, 

 which may be provisionally spoken of as the Scomberesocine 

 series (pp. 580, 581). 



11. As judged by the study of the ethmoid and suspensorial 

 regions, the Zanclida) and Acrouuridge are closely allied to 

 the Plectognathi, but the affinities of these forms must not ha 

 sought amongst living Physoclisti (pp. 582, 58o). 



Bibliography. 



97. Allis, E. p., jiui. — " The Morphology of tlie Petrosal Bone, and of the 

 Sphenoidal Region of the Skull of Aniia calva," ' Zool. Bull.,' vol. i, 

 1897, pp. 1—26. 



