120 JOHNS HOPKINS UNIVERSITY MOEPHOLOGICAL MONOGRAPHS. 



Fig. 2 of Plate VI is a dorsal view of a right-hand salpa and the 

 tubes which connect it with that part of the axial tube which pertains 

 to its body, while beyond it and partially hidden behind it is the body of 

 a left-hand salpa. 



Fig. 3 is a ventral view of the same two salpa3, but as this second 

 figure was reconstructed from the same set of sections, it is not reversed, 

 but the left-hand salpa is on the left side as it is in Fig. 2. In effect, 

 Fig. 3 is Fig. 2 as it would appear under a microscope when focused 

 down to its far side. 



Sections of a right-hand salpa at nearly the same stage are shown in 

 Plates XXXII and XXXIII at J-J', and sections of a left-hand salpa in 

 K-K'. The planes of these sections are shown by the cross lines in 

 the figures. The salpa? shown in the sections are a little younger than 

 those from which the solid figures were reconstructed, but the difference 

 is not very great. 



In Plate XXXIII, Fig. 9, cuts, on the right side below the level of the 

 endodermal tube, the tubes which connect it with the right halves of the 

 pharyngeal pouches ; all the tubes on the right side of this figure belong 

 to the right halves of the bodies, but they belong alternately to right- 

 hand and left-hand salpaB, while all those on the left, cut at the level of 

 their openings into the endodermal tube, belong to the left halves of the 

 bodies. Fig. 8, K-K', cuts the right and left connecting tubes of the left- 

 hand salpa, as is shown by the line K, 8, in Fig. 3, while Fig. 8, J-J', cuts, 

 as the line J, 8, in Fig. 2 shows, the left connecting tube of the right-hand 

 salpa at J', while on the right it cuts the oral end of the pharynx and the 

 ganglion. 



Fig. 7, K-K cuts, on the left, the left-hand connecting tube of the 

 left-hand salpa at 28 just before it expands into the pharynx, while on 

 the right at K it cuts the right connecting tube of the same salpa. The 

 right-hand salpa, J-J', is not shown in Fig. 7, but L-L' is essentially like 

 it, as is J-J' of Fig. 6. As the line J, 7, in Fig. 2 shows, this section cuts 

 the left pharyngeal tube of the right-hand salpa twice, once at the 

 extreme left of section L', and again near the middle of the section. 

 In Fig. 6, J-J', however, the left pharyngeal tube, 28, is cut only once. 

 The right end of section 7, ./, cuts the oral end of the pharynx at 27 and 

 the ganglion at s. 



