10 THE VOYAGE OF H.M.S. CHALLENGER. 



Lirus, Lowe. 



Leirus, Lowe, Tians. Phil. Soc. Cambridge, vi., 1836, p. 199. 



„ Jordan and Gilbert, Synopsis, 1882, p. 452. 

 Palinurus, De Kay, K York Faun. Fish., 1842, p. 118. 

 Hyperoglyphe, Giinth., Fish., i., 1859, p. 337. 



„ Liitken, K. dansk. Vidensk. Selsk. Skriv., xii., 1880, pp. 521, 602. 



Pammelas, Giinth., Fish., ii., 1860, p. 485. 

 Palinurichthyt!, Gill, Proc. Acad. Nat. Sci. Philad., 1S61, p. 20. 



On the British Museum coming into possession of a specimen of the Rudder-fish, 

 Pammelas perciformis, I was enabled to recognise the generic identity of that species 

 with the Australian Hyperoglyphe porosa. In the meantime Messrs. Jordan and Gilbert 

 pointed out the true relationship of the Rudder-fish, viz., that it was closely allied tu 

 Centrolophus bennettii from Madeira, for which Lowe had already proposed the generic 

 name of Leirus. Hyperoglyphe forms merely the extreme link of a chain of modifica- 

 tions of the form and structure of the dorsal fin as observed, in its most generalised form, 

 in Centrolophus pompilus or Schedop>hilus medusophagus. In these fishes the dorsal 

 fin is composed of extremely numerous, homogeneous soft rays, of which the anterior 

 only are unarticulated, though flexible. 



In other species of the same genera these unarticulated rays become stifier and more 

 or less spinous, and as they become stronger and more difi"erentiated, the number of 

 soft rays decreases. In Lirus perciformis the spinous and soft portions are completely 

 difi"erentiated, although they still form one continuous fin. In Lirus p>orosus (as I now 

 call the Australian species) a separation into two fins is indicated, but not fully 

 accomplished. But all these fishes form one natural group, the members of which 

 possess the complicated pharyngeal dentary apparatus. Hyperoglyphe, therefore, 

 should be eliminated from the Perch-like fishes, and placed as a synonym of Lirus 

 immediately after Schedophilus. Its teeth are minute, in a single series, and not 

 villiform or in a band. 



Lirus, like Schedophilus and Centrophilus, is a truly pelagic form. These fishes 

 follow floating objects or slowly moving animals (Medusae),' either for the purpose of 

 obtaining protection, or for the sake of food, as many small animals, like Crustaceans, 

 are attracted to the same objects. Some, at least, of the species live at considerable 

 depths, as we may gather from the testimony of fishermen, and safely conclude from 

 the softness of their skeletons ; and, probably, the young of all live at or near the 

 surface. 



1 The large Medusae on our coast (Pileina octopus) are almost always accompanied by young fishes. On the south 

 coast I found them to he Horse-mackarel, one large Medusa offering a temporary home to more than fifty of these young 

 fishes, which were from 2 to 3 inches long. Only once I found another species of fish among them, viz., a young 

 Whiting. 



