Intelligence and Miscellaneous Articles. 243 



physes and lock between them. The caudal vertebrae have the 

 facets for the chevron bones free from the articular margins, form- 

 ing large prominent unequal tubercles on the base of the centrum. 

 The coracoids are as broad as long, nearly square, not prolonged in 

 front of the humeral articulation. The scapulae are sickle-shaped, 

 thin towards the median line, and without any suprahumeral process. 

 The pubic bones are transversely oblong, and the ischial bones more 

 than usually triangular, owing to there being no forward prolonga- 

 tion to meet the pubes. The iliac bones are less expanded at the 

 proximal end, and relatively longer than usual. In the limbs the 

 ulna and radius approximate in form to those bones in Pliosaurus, 

 and the phalanges resemble those of Pliosaurus in not being com- 

 pressed from side to side. There are six polygonal carpal bones. 



3. "On the remains of Labyrinthodonta from the Keuper Sand- 

 stone of Warwick, preserved in the Warwick Museum." By L. C, 

 Miall, Esq. Communicated by Prof. Huxley, F.R.S., F.G.S. 



In this paper the author first noticed the remains of Labyrin- 

 thodonts from the Warwickshire Keuper, acquired by the Warwick 

 Museum since 1842, the date of Prof. Owen's memoir on this sub- 

 ject, and then reviewed the determinations of Prof. Owen. He 

 considered that Labyrinthodon ventricosus, Owen, is not a distinct 

 species, and that L. scutidatus, Owen, has not been proved to be a 

 Labyrinthodont. The species as identified by the author are as 

 follows : — 



Mastodonsaurus Jcegeri, Yon Meyer. 



pachygnathus, Owen. 



Labyrinthodon lejotognathus, Owen. 



Diadetognathus (g. n.) varvicensis, sp. n. 



In conclusion the author described some of the structural pecu- 

 liarities of the teeth of various Labyrinthodonts. 



XXVIII. Intelligence and Miscellaneous Articles. 



ON MAGNETISM. BY A. TREVE. 



IP we place between the poles of the large electromagnet of 

 -■- Euhmkorff the two extremities of the thick wire into which 

 the current passes from the pile — in other terms, if the circuit be 

 closed between the two poles, we get neither spark nor report ; but 

 when we open it a violent detonation is produced, " almost as 

 powerful as the report of a pistol," says M. A. de la Rive, who first 

 made the discovery. The learned Genevan physicist adds, " it 

 seems that the intensity of the extra current is greatly augmented 

 in this case by the influence of the poles of the magnet." This is 

 the phenomenon which I have essayed to fathom. 



Is it necessary to interrupt the current between the two poles in 

 order to obtain this effect ? No, If we increase the distance 



R 2 



