548 Mr. C. T. Began on a remarkable 



representing the fin. The length of the strip of paper in 

 centimetres gives, with approximate accuracy, the size of the 

 fin-surface in square centimetres. The sizes so obtained are 

 probably too small, for it is not possible to spread out to its 

 fullest extent the fin of a fish that has been preserved in 

 alcohol. The surface of the two pectoral fins of Exocoetus as 

 thus computed was 38'4 square centimetres, whereas the 

 corresponding area in the case of Hemirhamphus was 3'9 square 

 centimetres. That is to say, the superficial area of the 

 pectoral fins of Exoccetus is some eight or nine times that of 

 the corresponding surface in a Hemirhamphus of the same 

 size, whereas the weight of the external pectoral muscles is 

 only twice. 



As an item of negative evidence, it may be of interest to 

 state that a microscopical examination was made of disso- 

 ciated fibres of the external pectoral muscles of Gastro- 

 pelecus stellatus, Tetragonopterus eeneus, Exoccetus evolans, 

 and Hemirhamphus roberti, in order to ascertain if in the 

 "flying" form the cross-striping of the muscle-fibres was 

 more pronounced than in the control species. The fibres, 

 after being teased, were stained, some with picric-acid- 

 fuchsin (van Gieson's stain), some with borax-carmine : 

 some were examined in diluted glycerine, some in Canada 

 balsam. Examination of these slides failed to show any 

 marked differences in the degree of cross-striping. 



In conclusion, I have to thank Dr. S. F. Harmer, F.R.S., 

 Keeper of tlie Department of Zoology in the British Museum, 

 and Mr. C. Tate Regan, M.A., Assistant in charge of the 

 Fishes, for providing me with the specimens upon which the 

 observations recorded above were made. 



EXPLANATION OF PLATE XVI. 



Photograph of a skeleton of Gastropdecus stellatus (x £). Note the 

 great radially corrugated keel of bone, to the right and left side* 

 of which are attached the external pectoral muscles, which pull 

 down the fins. 



LXVIIL — Phallostethus dunckeri, a remarkable new 

 Cyprinodont Fish from Johore. By C. Tate Keg an, M.A. 



(Published by permission of the Trustees of the British Museum.) 



In 1904 (Mitteil. Naturhistorisch. Mus. Hamburg, xxi. 

 pp. 135-207) Dr. G. Duncker published a memoir on the 

 Fishes of the Malay Peninsula, and on page 171 mentioned 



