84 Mr. C. T. Regan on the 



structure to the Elopida ; the orbitosphenoid, however, is 

 ratlier anomalous ; it is placed far forward and forms an 

 interorbital septum extending from the parasphenoid to the 

 frontals, whilst posteriorly paired inferior ridges of the 

 frontals separate it from the alisphenoids. The protractile 

 prsemaxillaries exclude the maxillaries from the oral border, 

 and this feature distinguishes Aulopus from all Isospondyli. 

 In Iniomi other than the Aulopidse the post-temporals nearly 

 meet in the middle line above the supraoccipital, but are 

 attached by ligament to the epiotics, the maxillaries may 

 become reduced and closely attached to the prajmaxillaries, 

 the orbitosphenoid tends to disappear, and the parietals may 

 become separated by the supraoccipital (Myctophidaj). 



MiCROCYPRINI. 



The order Microcyprini includes the Cyprinodontidae and 

 Amblyopsidaj, usually considered to be allied to the Esocid^e, 

 which they resemble in fin-structure. 



Thoracostei. 



The order Thoracostei comprises the Gastrosteidai and 

 Aulorhynchidge. Swinnerton * has shown that the dermal 

 plate which appears as part of the coracoid is in reality a 

 distinct element. I cannot accept Jungersen's view that 

 these fishes belong to the Scorpaenoidei, although I readily 

 admit that the Aulostomoids are more distinct from the 

 Thoracostei than 1 recently considered them to be. 



SOLENICHTHTES. 



In a valuable memoir Jungersen f has pointed out the 

 features which show that the Aulostomoids, Oentrii<coids, and 

 Lopiiobranchii form a natural group, to which the ordinal 

 name Solenicht'nyes, recently proposed by nie for the Cen- 

 triscoids only, may be applied. 



Hypostomides. 



The Pegasidre show certain resemblances to the Scorpgenoid 

 Agonidse and Dactylopterida?, but they also exhibit some 

 important differences from them, especially in the truly abdo- 

 minal pelvic tins. 



Salmoperc^. 



I am unable to find a pneumatic duct in the Percopsidse, 

 %\hich have hitherto been said to be physostoraous. Tiie 



* Quart. Journ. Micr. Sci. xHx. 1905, p. .303. 

 t Vidensk, Selsk. Skr. (7) vi. ]008, p. 41. 



