W. C. M'INTOSH ON VALENCINIA ARMANDI. 79 



of separated muscular fasciculi {cl') between them and the basis-layer is a new feature in 

 the Carinellidse. In regard to the nerve-trunks on each side, it is an important fact that 

 while (in common with the ganglia) they lie clearly outside the proper circular and lon- 

 gitudinal muscular layers of the body-wall anteriorly, they gradually perforate both in 

 their progress backward to take up a position in the middle of the longitudinal layer. 

 Towards the tail the nerve-trunk again gets to the outer border of the latter, and almost 

 touches the circular coat (fig. 8, n) ; but it does not seem to get quite clear of the lon- 

 gitudinal fibres, some of which form a thin line externally. 



In regard to the vascular system, the general features are those of the Carinellidse. 

 There are two great longitudinal trunks (v, v) ; placed within the longitudinal muscular 

 layer of the body. In the oesophageal region (figs. 5 & 6) the trunks agree with 

 the arrangement in the common Carinella — that is, are situated outside the special 

 inner circular muscular layer. In the large Canadian Carinella, again, they lie within 

 this special layer, between it and the wall of the oesophageal region of the alimentary 

 tract. Anteriorly the trunks terminate in the new species in the vascular channels on 

 each side of the proboscidian canal, those of opposite sides communicating in front. The 

 arrangement, indeed, forms a kind of vascular mesh- work towards the tip of the snout ; 

 and the contents probably exercise an important influence on the mobile tissues of the 

 region when driven forward by the contraction of the great lateral trunks. At the 

 mouth (fig. 4) the latter lie nearly opposite the nerve-trunks on each side internally ; in 

 the anterior region of the body each vessel descends to a lower plane (fig. 6), while pos- 

 teriorly (fig. 8) the distance between the nerve and vessel greatly increases, the latter 

 having advanced inward almost to the wall of the centrally situated alimentary canal. 



Two other accessory systems yet remain to be described. The first of these consists of 

 a vessel with highly contractile walls (va, fig. 5), which lies anteriorly within the pro- 

 boscidian sheath, just above the point where the wall of the digestive canal meets it on 

 each side. It begins immediately after the mouth, and extends backward only a short 

 distance ; but its connexions anteriorly and posteriorly have not yet been ascertained. 

 There can be little doubt about the nature of this structure, which is quite different 

 from the collections of proboscidian corpuscles and coagulated fluid often seen in similar 

 positions. The wall of each vessel is definitely formed of a hyaline contractile substance, 

 in which numerous granules are imbedded. The physiological importance of this arrange- 

 ment is apparent, and it is especially interesting since the discovery of a regular series of 

 canals into the cavity of the proboscidian sheath of Ampkiporus spectabilis (Drepano- 

 jphorus, Hubrecht). The second system consists in the establishment of a channel on 

 each side underneath the great longitudinal muscular layer (vs, figs. 4, 5, & 6), as soon 

 as the upper arch of the proboscidian sheath is formed. These channels assume con- 

 siderable dimensions, but do not appear to be very contractile, since they have only 

 a hyaline film all round, and thus stand in marked contrast to the great vascular 

 channels inferiorly, or even the intra-proboscidian trunks above mentioned. They have 

 a lengthened course, but disappear towards the posterior end of the body. 



None' of the examples contained reproductive organs ; so that this department in 

 the group is still in need of further investigation. In the large Carinella from Canada. 



