176 REPORT— 1846. 



they must be distinguished by different special names according to their par- 

 ticular modifications in the same skeleton, as e. g. mandible, coracoid, ilium, 

 &c, I call such serially related or repeated parts ' homotypes.' The basi- 

 occipital is the homotype of the basi-sphenoid ; or in other words, when the 

 basi-occipital is said to repeat in its vertebra or natural segment of the ske- 

 leton the basi-sphenoid or body of the parietal vertebra, or the bodies of the 

 atlas and succeeding vertebrae, its serial homology is indicated. The study 

 of this kind of homologies was commenced by Vicq d'Azyr, in his ingenious 

 memoir ' On the Parallelism of the Fore, and Hind Limbs.' If we except 

 the complex and extremely diversified and modified parts of the radiated 

 appendages of the vertebral segments, to which Vicq d'Azyr restricted his 

 comparisons, the serial homologies of the skeleton are necessarily demon- 

 strated when the general and special homologies have been determined. 



In the present section of this Report I propose to consider some of those 

 examples of special homology which are least satisfactorily determined and 

 respecting which different opinions still sway different anatomists. Such 

 instances are fortunately few, thanks to the persevering and successful labours 

 of the great comparative anatomists of the last half-century : pre-eminent 

 amongst whom will ever stand the name of Cuvier, in whose classical works, 

 ' Ossemens Fossiles,' 'Histoire des Poissons,' ' Lecons d'Anatomie Comparee ' 

 (posthumous edition), and ' Regne Animal,' 1828, will be found the richest 

 illustrations of the special homological relations of the bones in the four classes 

 of vertebrate animals. 



Second only to Cuvier must be named Geoffroy St. Hilaire, whose 

 memoir on theBonesof the Skull in Birds as compared with those in Mammals, 

 in the ' Annales du Museum, t. x. (1807), forms an early and brilliant example 

 of the quest of special homologies, which could not fail, with other and similar 

 investigations of the same ingenious author, to impart a stimulus to that 

 philosophical department of anatomical inquiry*. In regard to the osteology 

 of the crocodile, we find Cuvier and Geoffroy engaged in a long parallel series 

 of rival researches, the results of which have had the happiest effects in de- 

 termining some of the most difficult questions of special homology. 



Nor Mas the co-operation of zealous cultivators of comparative anatomy 

 wanting in the eminent schools and universities of Germany. Goethe, in- 

 deed, had taken-the lead in inquiries of this nature in his determination, in.l 787, 

 of the special homology of that anterior part of the human upper maxillary 

 bone which is separated by a more or less extensive suture from the rest of 

 the bone in the foetus ; and the philosophical principles propounded in the 

 great poet's famous anatomical essays called forth the valuable labours of the 

 kindred spirits, Oken, Bojanus, Meckel, Carus, and other eminent culti- 

 vators of anatomical philosophy in Germany. 



It is not requisite for the purpose I have in view, to trace step by step the 

 progress of the special homological department of anatomy. Its present 

 state, as regards the skull of the Vertebrata, will be best exposed by the sub- 

 joined tabular view of the fruits of the latest inquiries. 



Table I. (See end of the Report.) 



This table gives at one view the general results of the researches into 

 the conformity of structure of the skull throughout the vertebrate series, 



* Oken's famous " Prograram, Uber die Bedeutung der Schadelknochen" was published 

 in the same year (1807) as Geoffrey's Memoir on the Bird's skull; hut it is devoted less to 

 the determination of ' special ' than of ' general homologies ' : it has, in fact, a much higher 

 aim than the contemporary publication of the French anatomist, in which we seek in vain 

 for any glimpse of those higher relations of the bones of the skull, the discovery of which 

 has conferred immortality on the name of Oken. 



