148 Mr. G. A. Boulenger on the 



combination of cliavacters indicating a very low position 

 among the Physoclists. Besides, tlie general appearance of 

 the pectoral arch is altogether unique, and the misinterpreta- 

 tion of the morphological value of its elements is no doubt 

 the reason why the true systematic relations of this fish have 

 so long been overlooked. 



In all the descriptions of the skeleton which have been 

 given since the well-known memoir of Bakker* the very 

 large bone to which the pelvis is attached has been identified 

 as the coracoid (or a synonymous element), the bone above it 

 being the scapula, to which four short bones (or, rather, three, 

 the anterior being fused with it) are attached, these being 

 regarded as the basals or pterygials of the pectoral fin. We 

 would thus have a condition, unique among Teleosteans, of 

 the pelvic bone articulating with the coracoid at a consider- 

 able distance from the clavicle. Therefore the really " abdo- 

 minal " position of the ventral fin has been questioned by 

 some authors, in the same way as the state of things in the 

 Sticklebacks was discussed before the homologies of the 

 elements of the pectoral girdle had been realized. On ex- 

 amining the shoulder-bones on a skeleton of Lampris luna, I 

 was h^truck by two things — first, that the disposition of the 

 articulating facets of the pterygials allows of a much greater 

 downward than upward movement of the rays of the pectoral^ 

 by which the fin can be pressed down close against the sides 

 of the body, and precludes the opposite vertical position — a 

 fact which I have been able to verify on a specimen in the 

 flesh. This mode of articulation seems so contrary to oui* 

 ideas that most figures t find stuff"ed specimens represent the 

 ],ectoral fin directed upwards, as in a Brama, to which the 

 Opah Avas believed to be related. Secondly, that the posterior 

 cf the supposed pterygials does not support rays and is alto- 

 gether unlike a pterygial, whilst its resemblance to a much 

 reduced coracoid is at first sight obvious. That it is not a 

 pterygial is conclusively proved by the fact, which I have 

 ascertained at the suggestion of my friend Prof. Howes, that 

 it is synchondrosially united with the scapula and the large 

 bone hitherto named coracoid by cartilage, whilst only liga- 

 ment intervenes between the true pterygials and the bones of 

 the primary shoulder-girdle. If, therefore, this be the 

 coracoid, the large bone between the scapula, the clavicle 



* ' Osteograpliia Piscium ; Gadi pracpertim Aeglefini, coniparati cum 

 Lampride guttato, specie rarioii.' Groningen, 1832. 



t Those of Guniierus, Norsk. Bid. Selsk. Skrift. iv. 17G8, pi. xii.; 

 Sowerby, Brit. Miscall, pi. xxii. (1834) ; andSmitt, Scandiu. FisL. p. 12S 

 (1893), are correct, being based on fresh specimens. 



