No. 2. — Reports on the Scientific Results of the Expedition to 

 the Eastern Tropical Pacific^ in charge of Alexander Agas- 

 siz, hy the U. S. Fish Commission Steamer " Albatross" 

 from October, 1904, to March, 1905, Lieutenant Commander 

 L. M. Garret, U. S. iV., Commanding. 



XIII. 



The Characters of Atelaxia, a new sub-order of Fishes. 



By Edwin Chapin Starks. 



The specimen of Stylephorus chordatus upon which this paper is based 

 was obtained by the Agassiz Expedition to the Eastern Tropical Pacific 

 in 1904-1905, at station 4715, which is just south of the Galapagos 

 Islands. The specimen was taken somewhere between a depth of three 

 hundred fathoms and the surface, and was referred to me by Mr. Agassiz 

 through Dr. Evermanu for study of its osteological characters. 



This is the second specimen known. Before the above date the species 

 was known only from a specimen (now in the collections of the British 

 Museum) taken about the year 1790 in the western Atlantic between the 

 islands of Cuba and Martinique. 



The distinctive characters of the Stylephoridae are unique, and of such 

 value that they may be used to define a suborder characterized as 

 follows : — ■ 



Atelaxia. 



Vertebrae consisting of centra only and without neural or haemal spines or 

 other processes ; the opposing halves of the hyoid unconnected and remote from 

 each other ; the branchiostegal rays at the upper edge of the ceratohyal and in- 

 cHned upward ; the palato-quadrate bar atrophied ; the lower pharyngeals con- 

 cealed by skiu and much reduced ; the ethmoid far anterior to the vomer and 

 supported by a projection from the parasphenoid ; no obitosphenoid present ; the 

 caudal divided and part of the rays turned upward, the lower three enlarged and 

 produced backward into a long process. 



Minor characters of the Atelaxia may be included in the following definition of 

 the family. 



VOL. LI I. — NO. 2 1 



