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
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