ON THE (ESOPHAGUS OF THE RUMINANTIA. 61 



Pinally, the Euminant's oesopliagus differs widely from the 

 human as regards the microscopic character of its muscular fibre ; 

 for while in the human gullet there is a mixture of striped and 

 unstriped fibres, in the Euminant's they are all of the striped 

 variety. 



In conclusion, I have to acknowledge my obligations to my 

 friend Mr. Deas, to whose kindness I owe the beautiful and very 

 accurate drawings which illustrate this paper. 



EXPLAIJATION OP THE PLATE. 

 Plate III. 



Fig. 1. Portion of sheep's gullet, twice the natural size (seen from within). The 

 fibres of the internal layer, c c, are seen decussating and running into 

 the external layer, b b ; while at A is seen a ?2ora-decussating bundle 

 passing outside the decussation, from the outer layer of the one side of 

 the decussation to that of the other side. 



Fig. 2. The entire circumference of a sheep's oesophagus, seen from within 

 (natural size). It has been simply slit open and dissected. Above, 

 a', a", are seen the two lines of decussation ; b, a bundle of fibres 

 which has not decussated at the decussation a' ; and c, a similar 

 bundle which has not decussated at a", d, a bundle of fibres of the 

 inner layer which decussates at the line of decussation a" ; and e, a 

 similar bundle which decussates at the line a', d runs up to form b, 

 and E goes to form c, both in the outer layer ; below r they separate 

 into their finest fibres and interdigitate one with another. G G, outer 

 layer. 



Fig. 3. Two portions of the oesophagus of a sheep (natural size), to show the 

 difierence between the inner and outer aspects of the line of decussa- 

 tion. In A it is seen from the inside. All the fibres decussate, so 

 that the decussation is sharp and well defined ; but on the outside, b, 

 it is much obscured by the non-decussating fibres, which, instead of 

 dipping down as in A, run across from one side of the line to the 

 other. G G, outer layers, d, inner layer. 



Descriptions of New Species of Hymenopterous Insects from the 

 Islands of Sumatra, Sula, Grilolo, Salwatty, and 'New Gruinea, 

 collected by Mr. A. E. Wallace. By Fkedeeiok Smith, 

 Assistant in the Zoological Department, British Museum. 

 Communicated by "W. W. Saundees, Esq., Y.P.L.S. 

 [Plate IY.] 

 [Read June 2, 1864.] 



The collections of Hymenoptera which are described in the fol- 

 lowing list contain several insects of especial interest. Three new 



LimS". PEOC. — ZOOLOGY, TOL. VIII. 6 



