7. sinB.vi.DiTis. 175 



transverse process of the vertebra. The first pair of ribs have double 

 heads ; but the anterior head on both sides is very incompletely deve- 

 loped, and on the right side completely detached from the remainder 

 of the bone ; it has a pointed end below, merely applied to the main 

 part of the rib ; so that if it had been lost in maceration, this rib 

 might have been supposed to be simple. On the left side it is anchy- 

 losed, but very slender. It would be interesting to ascertain, by the 

 examination of younger specimens, whether this anterior head has 

 always a separate centre of ossification, as it is not improbable that 

 this singular double-headed bone is in reality formed by the coales- 

 cence of two originally distinct ribs. The second, third, and fourth 

 ribs have small capitular processes. The stylo-hyals are very flat, 

 but not so broad proportionately as in the Java Whale, being 11" 

 long and 3^" in greatest width. The bones of the fore limbs present 

 the same general characters and proportions as in the Leyden spe- 

 cimen from the Zuyder Zee. The sternum is absent. 



" This specimen has been previously mentioned in this paper as 

 an example of Sibbaldiits Jatkeps, Gi'ay, presenting some interesting 

 individual deviations from that at Leyden, referable to the develop- 

 ment of the two skeletons not having proceeded pari passu in all 

 parts of the system." — Floiver, P. Z. S. 1864, 417. 



** Dorsal fin very s^nall, far behind, and placed on a thick prominence, 

 nibs 14 . 14 ; fiist short, sternal end very broad and deeply notched, 

 Sternwn ivith a broad short hinder lobe. Os hyoides transverse ; sides 

 slender ; hinder edge cut out in the middle. 



2. Sibbaldius borealis. The Flat-hack. 



Sibhaldus borealis, Gray, P. Z. S. 1864, 223 ; Ann. ^ Mag. N. H. 



1864, xiv. 352. 

 Baleine d'Ostende, Van Breda, en letter bock, 1827, 341 ; Dubar, Os- 



teographie, BrKxelles, 8vo, 1828, t. 1-10; Bernaert, '■^Notice sur la 



Baleine echouee prl'S d'Ostende,^' Paris, 1829. 

 Baleinoptere d'Ostende, Van dcr Linden, 1828, Bruxelles, 8vo. 

 The Osteud Whale, Guide to the Exhibition at CJiaring Cross, tvith 



drawings by Scharff. 

 Groat Northern Rorqual, " R. borealis, Lesson,^'' Jardine, Nat. Lib. 



125. t. 5 {from Schurf). 

 Balsena borealis (part.), Fischer, Syn. 524 (from Dubar). 

 Bahenoptera Rorqual, Dewhurst, Loudon Mag. N. H. 1832, v. 214. 

 Balfeuoptera gigas, Eschr. Sc Reinh. Nat. Bidrag, af Groenland, 1857 ; 



Lilljeborg, I. c. 56, 57 ; Malmgren, Arch. Naturg. 1864, 97. 

 Pterobalasna Boops (part.), Eschr. K. Dansk. Vidensk. 1849, 134. 

 Pterobalfena gigas, Van Beneden, Mem, Acad. Roy. Sci. Brux. 1861, 



xxxii. 37, 463 (not characterized). 

 Femcde : — 



Balffiuoptera Boops, Yari-ell, Proc. Zool. Soc. 1840, 11. 

 Baltenoptera tenuirostris. Sweeting, 3Iag. Nat. Hist. 1840, iv. 342. 



Inhab. North Sea. 



" A whale was observed floating dead in the North Sea between 

 Belgium and England," and towed into the harbour of Ostend on 

 the 4th of November 1827. The skeleton was exhibited at Charing 

 Cross, and is now, I beheve, in the United States. 



