Deep-hodied Species of Diplom jstus. 3 



Diplomystus Birdi^ sp. n. (PI. I. fiLi^.s. 2-4.) 



Type. — Nearly complete fish ; British Museum. 

 i>p. Char. — A small {.leoj)-bo(-lied 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. ^laximuni 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 tiiirds of the same 

 measurement. Abdominal vertebrjB 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 2o rays. Dorsal ridge-scales 

 with a prominent median acumination ; ventral ridge-scales 

 nearly regular in size, not excessively enlarged, sharply 

 pointed. 



Obs. The species thus defined was first observed by the 

 present writer in the collection of the ilev. 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 ty])e specimen. The species seems to have 

 been moderately robust, for the various examples arc much 

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

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

 while 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 tiie pectoral arch 

 somewhat displaced back^vards. The deeply cleft caudal \\i\ 

 is indicated in figs. 3 ajid 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 rid;;e- 

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

 nent median [)oint and some a[)])arcntly also with one or two 

 pairs ot lateral denticulations. The squamation of the flanks 

 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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