1903.] 



AXATOMY OF THE HAMADRYAD SXAKE. 



325 



coeloni divided by metamerically arranged transverse septa like 

 that of a typical Annelid. This, however, is obviously not the 

 case unless we are to adopt the totally improbable view that 

 the trachea communicates directly with the coelom. These 26 or 

 27 chambers, extending from the chin, to the lung, do not, so 

 far as I -have been able to ascertain, communicate with each 

 other. They correspond fairly, though not accurately, with the 

 intercostal branches of the anterior vertebi'al artery, and in the 

 following way : — Those arteries arise at approximately equidistant 

 intervals and bury themselves in the thickness of the parietes in 

 the dorsal middle line. Along their course they are supported 

 by the membranous partitions in question, which adhere to them 

 from their origin to their disappearance in the parietes. Only 

 four of the total series of over thirty of these arteries were not 

 so supported, and only two "septa" were devoid of an arterial 

 companion. On the opposite side of the body the vertebral veins 

 have a similar relation to the " septa." In addition to the 



Text-fio-. 39. 



A portion of trachea from dorsal surface of Ophiophagus, showing:, A, perforation 

 leading into air-sac, and, B, circular thinning of tracheal membrane. 



principal tracheal foramina there are smaller ones which lie 

 between the larger and just between two adjacent ah'-sacs. The 

 arrangement of these, however, is not regular. I could only 

 count four or five of them. I imagine that they correspond to 

 smaller intei^calaiy sacs, of which there was distinct evidence, 

 lying between the larger ones. Finally here and there, and also 

 lying between the primary sacs, were regularly rounded thinnings 

 of the tracheal membrane (text-fig. 39, B) which may be looked 

 upon as — if the expression be allowed — imperforate foramina. I 

 could detect no evidence of intercalary sacs in connection with 

 them ; but they are ready, as it were, to form such sacs. 



In a second example of this Snake, also a male, I examined the 

 air-sacs of the neck, which I found to agree in all essentials with 

 those of the first specimen. There are, ho^veve^■, I'ather fewer 



