Ill) CALIFORNIA ACADKMV OK SCIENCES. 



PLATE XXXIX. 



PONTODKILUS MICHAELSENI. 



70. CrosH-sectioii of the budy iu samite xi, showing the relative thickness of the septa and budy-wall, the sepia 

 being very uiiich cupped, showing the msophagus, etc., of the somite ix, as well as the septnm 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. ;//. septal gland snrroiuuliug the connecting vessels iu somite ix. There are five pair of 

 these glands, one each in v, vi, vii, viii, ix. 



7 1.V. One of the nephridia isolated. ;/. /. posterior lobe of the peritoneal sac of the nephridinm. a. I. anterior 

 lobe of the same. n-. windings of the canals where the two folds meet. }>■/• and a./, posterior and anterior 

 folds of the canal, n. p. nephroporo. n. at. uephrostome. spr. spur with four canals. Iir. bridge. 

 bl. V. blood vessels on the uephrldiuni. 



71B. Nephrostome isolated, m. marginal cells, iv. d. wide duct. hic. neck iu which the narrow duct is seen to 

 be branched. 



7-. An enlarged and souuwhat diiigrauimatic drawing of the course of the ducts, etc., of the nephridiuui. The 

 letters indicate the same as in the preceding figure. The canals have been representtd as further apart 

 than they are in reality, otherwise their course could nut have been clearly delineated. Wheu the uephridium 

 is viewed from above mounted in glycerine, the outlines of the canals are only dimly discernible, being giently 

 obscured by peritoneal cells and blood vessels, neither of which have been delineated. The shape of the 

 neck varies to some extent, iu some specimens being much wider than in others. 



73. Various forms and sizes of blood-glands from the supra pharyngeal and septal salivary glands. Drawn from 

 paratiue sections, hardened in Formaline, and stained: ii. orange (>. alcohol, Ehrlicb's hiematoxylou amm. 

 h. rose aniline in hydrochloric alcohol, Bismark brown, and Ehrlich's ha^matoxylon. The latter combination 

 gives by far the finest results, clearly diSTerentiatiug the blood from the gland-secretion, this being very 

 imperfectly done by the orauge (J. 



