Deep-hodied Species q/' Diplom jstus. 3 



Diplomystus Birdi, sp. u. (PI. I. fi^s. 2-4.) 



Type. — Nearly complete fish ; British Museum. 

 Sp. Char. — A small deep-bodied species, attaining a length 

 . of about 0"06 metre. Dorsal region much elevated, the margin 

 rising to the origin of the dorsal fin, where it is almost angu- 

 larly bent ; caudal region relatively long. Maximum depth 

 of trunk nearly or quite as great as its length from the pectoral 

 arch to the base of the caudal fin ; length of head with 

 opercular apparatus equalling about two thirds of the same 

 measurement. Abdominal vertebrse 14 to 16, caudals 18 in 

 number. Dorsal fin arising well in advance of the middle of 

 the back, with about 16 or 18 rays; anal fin not completely 

 behind the dorsal, comprising 25 rays. Dorsal ridge-scales 

 with a prominent median acumination ; ventral ridge-scales 

 nearly regular in size, not excessively enlarged, sharply 

 pointed. 



Ohs. The species thus defined was first observed by the 

 present writer in the collection of the Rev. William Bird, 

 A.M., of Abeih, now in the Museum of the Syrian Protestant 

 College, Beyrout. It may therefore be named D. Birdi, in 

 honour of one of the most devoted students of Syrian geology. 

 There are, however, several examples of the fish also in the 

 British Museum, and three of these are shown of the natural 

 size in Plate I. figs. 2-4. The second (fig. 3) is to be 

 regarded as the type specimen. The species seems to have 

 been moderately robust, for the various examples are much 

 distorted by crushing ; but the study of a series suggests that 

 the type specimen shows the nearly normal form of tlie trunk, 

 Avhile the head is better preserved in the original of fig. 2. 

 Figs. 3 and 4 show the small pelvic fins opposed to the origin 

 of the dorsal; and the first has one side of the pectoral arch 

 somewhat displaced backwards. The deeply cleft caudal fin 

 is indicated in figs. 3 and 4. The much-thickened neural 

 spines supporting the dorsal ridge-scales are shown in all the 

 specimens, and intermuscular bones are conspicuous both 

 above and below the vertebral column. The dorsal ridge- 

 scales seem to have been broader than long, with one promi- 

 nent median point and some apparently also with one or two 

 pairs of lateral denticulations. The squamation of the fiaiiks 

 is shown to have been very thin. 



Diplomystus Birdi is most closely related to the associated 

 D. brevissimus, but differs in the much deepened form of its 

 trunk and the arched contour of the back. 



Formation and Locality. Upper Cretaceous ; Ilakel, 

 Mount Lebanon. 



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