PHILOSOPHICAL TRANSACTIONS. 



Contents op Paet III, 1880. 



XXI. A Memoir on the Single and Double Theta-Functions. By A. Cayley, 

 F.E.S., Sadlerian Professor of Pure Mathematics in the University of 

 Cambridge. 



XXII. Eevision of the Atomic Weight of Aluminum. By J. W. Mallet, F.E.S., 

 Professor of Chemistry in the University of Virginia. 



XXIII. Description of some Eemains of the Grigantic Land-Lizard (Megdlania 

 prisca, Owen), from Australia. — Part II. By Professor Owen, C.B., 

 F.E.S., he. 



XXIV; On the Ova of the Echidna Hystrix. By Professor Owen, C.B., F.E.S., 

 &c. 



XXV. On the Determination of the Constants of the Cup Anemometer by Experi- 

 ments with a Whirling Machine. — Part II. By T. E. Eobinson, D.D., 

 F.E.S., &c. 



XXVI. On the Dynamo -electric Current, and on Certain Means to Improve its 

 Steadiness. By C. William Siemens, D.C.L., F.E.S. 



Index to Part III. 



Contents oe Paet I, 1881. 



On the Structure and Development of the Skull in the Batraclna — Part III. 

 By W. X. Paekee, F.E.S. 



PHILOSOPHICAL TRANSACTIONS. 

 Part III, 1880, price £1 Is. 

 Part I, 1881, price £2 10s. 



Extra volume (vol. 168) containing the Eeports of the Naturalists attached to the 

 Transit of Venus Expeditions. Price £3. 



Sold by Harrison and Sons. 



Separate copies of Papers in the Philosophical Transactions, commencing with 1875, 

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