110 
70. 
71A. 
~I 
to 
73. 
CALIFORNIA ACADEMY OF SCIENCES. 
PLATE XXXIX. 
PONTODRILUS MICHAELSENT. 
Cross-section of the body in somite xi, showing the relative thickness of the septa and body-wall, the septa 
being very much cupped, showing the cesophagus, etc., of the somite ix, as well as the septum and ciliated 
rosettes of x. v.v.x. the ventral vessel in x where it connects with the hearts. v.v.ix. the two forms of 
the ventral vessel. gl. septal gland surrounding the connecting vessels in somite ix. There are five pair of 
these glands, one each in vy, vi, vii, viii, ix. 
One of the nephridia isolated. p./. posterior lobe of the peritoneal sac of the nephridium. a./. anterior 
lobe of the same. w. windings of the canals where the two folds meet. p./. and a. /. posterior and anterior 
folds of the canal. xn. p. nephropore. x. st. nephrostome. spr. spur with four canals. br. bridge. 
bl. v. blood vessels on the nephridium. 
Nephrostome isolated. m. marginal cells. w.d. wide duct. nec. neck in which the narrow duct is seen to 
be branched. 
An enlarged and somewhat diagrammatic drawing of the course of the ducts, etc., of the nephridium. The 
letters indicate the same as in the preceding figure. The canals have been represented as further apart 
than they are in reality, otherwise their course could not have been clearly delineated. When the nephridium 
is viewed from above mounted in glycerine, the outlines of the canals are only dimly discernible, being greatly 
obscured by peritoneal cells and blood vessels, neither of which have been delineated. The shape of the 
neck varies tosome extent, in some specimens being much wider than in others. 
Various forms and sizes of blood-glands from the supra pharyngeal and septal salivary glands. Drawn from 
paratine sections, hardened in Formaline, and stained: a. orange G. alcohol, Ehrlich’s hematoxylon amm. 
4. rose aniline in hydrochloric alcohol, Bismark brown, and Ehrlich’s hematoxylon. The latter combination 
gives by far the finest results, clearly differentiating the blood from the gland-secretion, this being very 
imperfectly done by the orange G. 
