(34) 



oscillations of' this kind than meteorological observations made at 

 tropical stations. 



If the outcome arrived at by the arrangement of barometric daily 

 means for Batavia is considered to afford some evidence or indica- 

 tion foj' an oscillation periodic in 25.80 days, a mucii greater 

 probability mnst be attached to tlie real existence of tliis flnctuation 

 in the observations of magnetic declination made at Grreenwich. 



Anatomy. — "(M tkc Form <>f tkc Trnnk-nniotoine." (First Com- 



mnnication). By Piof'. .1. W. LAN(fE].AAN. (Communicated by 



Prof. T. Place). 



The segmented plan of construction of the vertebrate animals, 



most marked in the nniscular system, has led to tiie conception of 



the myotome. 



Two methods are chiefly employed in establishing the form of 

 this myotome. The first method is based on the hypothesis of the 

 primary connection between muscle and nerve ; the second, a more 

 direct one, is based on the dissection of the intersegmental tissue. 

 Both methods seem equally restricted in their application, as can be 

 concluded from the researches of Bakdkkn ') ; moreover there is 

 reason to believe, that they will uol always yield concordant results. 

 Tlie second method is followed iu this I'esearch. 



I. Traiik-iinjotoine of Fetiviiiijzoti j/uciati/is. (Fig. 1). 



The trunk-myotome of the 

 adult animal has in general 

 the form of a crescent, the 

 cornua being directed to- 

 wards the cranial end of the 

 body and slightly inclined 

 to each other. The dorsal 

 cornu (fig. II CD) reaches 

 r to the mid-dorsal line, while 

 the ventral cornu (fig. II 

 U^ CV) ends at the mid-ventral 

 line of the body. Both cornua 

 diliei' in length, the dorsal 

 being about 7? longer than 

 the ventral, and while both 

 reach to the mid-plane of 

 Fig II. the body, they are slightly 



torquated in respect to each other. 



1) Anal. Anz. Bd. XXIII, N". lU/11. 



Ci. (■ 



