260 PKOFESSOE OWEN ON CNEMIOENIS. 



mandible and the fronto-lacrymal apex of the cranium, and in the spheno-mastoid bridge 

 crossing the tympanic cavity, Cereopsis agrees with Cnemiornis. 



§ 3. Vertebrce. 



Of the cervical vertebrae of Cnemiornis I have now as many as exemplify the usual 

 modifications of their size, shape, and processes in this part of the spinal column of 

 birds, also the general characteristics of such part in Lamellirostrals by a number of 

 vertebrae above the average in the feathered class ; but the precise sum of cervicals 

 waits a better opportunity of obtaining the skeleton of the same individual than has 

 hitherto offered, and one knowingly availed of. 



The main modification of the cervicals of Cnemiornis, as compared with those of other 

 Natatores, is the greater extent of ossification of the neural arch. The parial hyp- 

 apophyses also converge in the eleventh cervical to contact at their free ends ; and those 

 in the twelfth cervical have coalesced to form a complete inferior bony arch or ring. 

 This structure I have not observed in any other Anserine or Lamellirostral species ^. 



Both characteristics of Cnemiornis are shown in the figures of the cervical vertebrae 

 in my first Monograph on the genus. The views chosen for this purpose gave, accord- 

 ingly, the upper ^ the under \ with the fore ' and hind \ surfaces of the vertebrae. In 

 the present paper I therefore give a side view (PI. XXXVI. fig. 6), and, for comparison 

 with fig. 4, pi. 63, Trans. Zool. Soc. vol. v., a corresponding view of the homologous 

 cer^ical in Cereopsis (ib. fig. 7) and Tachyeres (fig. 8). 



The cervical vertebrae in Anserines, which have a single hj'papophysis at the hind 

 part of the centrum, beneath the hind articular surface, are the two or three which 

 follow the axis. After a certain number without lower processes a pair of praehypapo- 

 physes (PI. XXXVI. figs. 7 & 8, ph) begin to project from beneath the costal arch, 

 approach each other in succeeding vertebrae without coalescing, and gain the under 

 surface of the centrum as they lengthen. They then usually abruptly cease, and are 

 replaced by a single hypapophysis at the middle of the fore half of the centrum ; and 

 this is continued, usually with decreasing length or suppression, to the dorsal series, 

 where, after the first, the hypapophysis reappears with increased length. 



The cervical vertebra of Cnemiornis the subject of figs. 1-4, pi. 63 {torn, cit.), 

 answers by the position of its hypapophysis to the third or fourth cervical in Cereopsis 

 and Tachyeres. My present series shows it to be the fourth, and also includes the third 

 cervical, of which I give a side view in PI. XXXVI. fig. 1, with a similar view of the 

 homologous vertebra in Cereo2)sis (ib. fig. 2) and Tachyeres (ib. fig. 4). 



' Twelve cervical vertebra were collected by the Hoe. Capt. Prazer in the Earnscleugh Cave, and are attri- 

 buted to the same individual bird by Dr. Hector. 



' It occurs in other groups of Aves ; the illustration in my ' Anatomy of Vertebrates,' vol. ii. p. 40, fig. 25, 

 is from a PeHcan. 



^ Trans. Zool. Soc. vol. v. pi. 63. fig. 3. ' lb. ib. fig. 4. = Ib. ib. fig. 1. • lb. ib. fig. 2. 



