164 



easily recognisable in the fish, but much more obscure in higher 

 animals. 



3. The definite type of muscular arrangement consists of a series of 

 fibres connecting the component arches of the vertebral segments of the 

 body. 



4. These vertebral segments are united by five typical muscle layers 

 most regularly developed in the thoracic paries, and which may be 

 named thus : — 



1. Exo-Interneurapophysial or hsemapophysial type. 



2. Ento- „ „ 



3. Spino-neurapophysial or hsemapophysial type. 



4. Basio- ,, 



5. Interspinal. 



5. These segments are most regular in the regions in which the bony 

 skeleton is most typically developed, and vary in the direct ratio of their 

 specialization of function. 



6. The muscles of the vertebrate limb are likewise arranged as 

 modification of a type which is not completely represented in either of 

 the human limbs. 



7. "When the function of any muscle is perfectly executed by 

 another, from the consolidation or alteration of the relative arrange- 

 ment of segments, the muscle so superseded becomes diminished or sup- 

 pressed. If the assumption of function be not perfect, the supersedence 

 is not complete, but coalescence takes place. 



XXIY. — On the Occtjeeence of the Numbee Two in Ieish Peopee 

 Names. By P. W. Joyce, A. M. 

 [Read January 13, 1868.] 



A caeeeul study of ancient proper names is one of the means by which 

 we may hope to arrive at a solution of that most difficult of all histori- 

 cal questions, the origin of races. In our own country, an examina- 

 tion of this kind may help to throw some light on the much disputed 

 question, where our forefathers came from — whether, as some say, they 

 crossed over from "Britain, urged on by the never-ceasing western 

 movement of the great Celtic population, or came direct from Spain, as 

 our own most ancient traditions steadily assert, or from any other part 

 of the Continent. 



In pursuing this inquiry, we may either examine and compare the 

 root words of which the names are composed, or investigate the manner 

 in which names were imposed by different races. There are certain 

 general principles common to the nomenclature of all countries; 

 but a careful examination would be pretty sure to show, that the 

 name system of each particular people possesses some special peculia- 

 rities of its own. The object of this paper is to draw attention to a 

 curious characteristic of this kind which I have observed in Irish 



