EXPLANATION OF PLATE, Vil 
Fic. 1.—Lahorta hortensis: a somewhat diagrammatic representa- 
+) 
3? 
tion of the general form of the animal. Free dorsal setz 
not represented. 
2.—Anterior part of body, from above (living specimen), to 
show pigmentation, etc.: bch = branchial process ; c.g. = 
cerebral ganglion of left side ; comm. == commissure between 
cerebral ganglia of the two sides; m. = level of mouth, 
which is indicated by an irregular black line, showing 
through the cerebral ganglia ; oes. = cesophagus ; ph. = out- 
line of pharynx; pr. = thickened epithelium of pro- 
stomium ; s. = sete contained in branchial process. 
3.—A segment in the middle of the body, showing arrange- 
ment of blood-vessels : a.v. = afferent vessel to gill; bch. = 
epithelium of branchial process; d.v. = dorsal vessel ; 
é.0, = efferent vessel; int. = intestine; s. = sete im 
branchial process; sp. septum, to which on the other 
side the efferent vessel appears to be attached. 
5 4—6.—Posterior end of body of Dero sp.; from various speci- 
mens, in various conditions of contraction or expansion. 
In fig. 4 the margin of the funnel is seen, and the inser- 
tions of the gill-processes are visible within it by trans- 
parency. In fig. 5 the gills and palp of one side only are 
shown; the third gill appears as a projection of the 
margin of the funnel; the fourth small (dorsal or anterior) 
gill was noted in this case as being apparently single and 
median; the outline of the funnel is shown within by 
transparency. Fig. 6 is seen from the dorsal surface 
looking into the funnel; the fourth (anterior) gills are not 
distinguishable as separate projections. 
pb. = palp; s.4. = sensory hairs; g!.—¢*. = gill-processes. 
