358 



PROF. A. H. GARROD ON THE 



[Apr. 1, 



also pointed anterior ends, running inwards almost as much as does 

 the second, in a manner very characteristic of all the genera in which 

 the second semiring is pointed and prolonged. There is no trace of 

 any interval between the penultimate and last tracheal rings. Between 

 the last and the first bronchial semiring the interval is a capacious 

 ovoid. That between the first and second bronchial semirings is elon- 

 gate and shallow, not deeper than the lower bronchial intervals. Cac- 

 cabis saxatilis agrees with C. rufa, except that in the former there 

 is a slight development of antero-lateral interannular intervals between 

 the lower tracheal rings, as in Argus, the account of which follows. 

 In Argus giganleus the lowermost tracheal rings are separated by 



Fig. 5. 



Fig. 6. 



Front view. 



Back view. 



Argus giganteus. 



narrow intervals in front, where in the middle line the last three 

 fuse and ossify into a mass whose lower border descends but little 

 below the level of the inferior margin of the unmodified last ring 

 for the articulation of the anterior extremities of the first bronchial 

 semirings. Posteriorly the pessulus joins the penultimate ring, the 

 two hinder ends of the last ring being well separated. The first 

 bronchial semiring is large and strongly convex downwards from 

 the development at each of its ends of upturned articulating pro- 

 cesses, at the junction of which with the horizontal portion of the 

 tube the second semiring articulates along its lower border. The 

 interval between each lateral element of the last tracheal ring and 

 its corresponding first bronchial semiring is considerable, tending 

 to a quadrate form, whilst that between the first and second semi- 



