Cope.] *h [Jan. 17 



Hemibranchii and LoptiobrancMi. It agrees with the former, also, in 

 the development of the premaxillary bone over the whole arc of 

 the mouth, and the reduction of the superior pharyngeals to one, the 

 third. The undivided, sessile post-temporal, and simple basis cranii 

 are characters of the Hemibranchii. The absence of anterior dorsal fin 

 is in many of them, as is also the enlargement of the anterior vertebrae, 

 and the sutural interlocking of the centra, and union of the plate-like 

 neural spines. The presence of a strong third superior pharyngeal bone, 

 and the superior branchihyals with the laminiform branchial processes, 

 separate the genus from the Lophobranchii. 



Thus this genus, whose true systematic position has been so long 

 doubtful, appears to be nearer to the Hemibranchii than to any other 

 order. But there are some features in which it differs from these also. 

 The scapula is horizontal instead of vertical, throwing the superior 

 margin of the pectoral fin to the level of the inferior rays, and behind 

 them . The fin is thus horizontal and on the plane of the abdomen, instead of 

 occupying the universally elevated position seen in Hemibranchii. By this 

 arrangement, the coracoids become horizontal, and they are also entirely 

 transverse, enclosing the branchial cavity behind. The interclavicles 

 are narrow, and attached to their inferior surface. A more important 

 difference is seen in the opercular apparatus ; the inter and sub-opercular 

 are not distinguishable from the operculum. 



Thus there is a remarkable range in the production of the mouth in 

 this series. In Pegasus inferior, in G aster osteus terminal, and in the 

 three remaining families very much produced. 



The Pegasidce suggest the connection of this order to the Scypho- 

 bra nchii through the Aspidophorida. In the latter the single basin-shaped 

 third superior pharyngeal is similar (but the superior branchihyals are 

 present) ; the pust-temporal is coossified, and though furcate is roofed 

 over by bone. The femora are roof-shaped, and the sub-operculum much 

 reduced. 



Gasterosteus aculeatus, L., var. trachurus. 



From Alaska, closely resembling specimens of the same variety from 

 Godhavn, Greenland, brought by Dr. I. I. Hays, but with rather longer 

 head and more slender dorsal spines. 



PERCOMORPHI. 



Aspidophor idee. 



Aspidophorus accipenserinus, Pallas. 



Gottidee. 



Blepsias bjxobus. Cuv. Val. 



Said to have been caught in flying over an Indian's canoe off Sitka ; the 



great development of the pectoral fins renders it quite probable that 



this species can make short flights. Deposited in the Academy of 



Natural Sciences by Dr. John B. White. 



Blepsias cirrhostts. Cuv. Val. 

 Alaska. 



