116 CALIFORNIA ACADEMY OF SCIENCES. 



PLATE XLII. 



ECLIPIDRILUS FRIGIDUS. 



83-91. Eeprespiit somewhat diagrammatio views of transverse section of the body, respectively through somites iii, 

 iv, ix, X, X, xi, xi, xiv and xv. Of somites x and xi sections from the anterior and posterior parts are shown. 

 The following letters are common and indicate the same in each one of the figures: v. v. ventral vessel. 

 d. V. dorsal vessel, int. intestine. I. m. longitudinal muscular layer. t. m. transverse muscular layer. 

 V. c. ventral nerve cord. m. muscles and connective tissue uniting the intestine and body-wall. sp. a. 

 sperm-sacs. c. v. connecting vessels, cut in various places, phx. pharynx, shown to be developed only on 

 the upper side of the alimentary canal. 



84. The intestine is here seen only to be connected with two superior muscular fascicles with the body-wall. The 



connecting vessels between the ventral and dorsal vessels are covered with glandular cells, the contents of 

 which stains deeply with hiematoxylon, and are of a different nature from the chloragogic cells. 



85. Section through the first clitellar somite ix. el. clitellar layer, splh. spermatheca. s/jj. spermatoza. 



86. Section through somite X. In this specimen both the spermatheca project into somite x. The bloodvessels 



which are seen in the sperm-sacs and surrounding the spermatheca are the anterior part of the anterior pair 

 of lateral vessels, which project no further than here. 



87. Section through the posterior part of x cutting through the atrium and penis. The ciliated rosettes were not 



seen in this section, only some parts of the spermduct. The blood vessels seen surrounding the penis and 

 atrium are the anterior parts of the posterior pair of lateral longitudinal vessels. 



8S. Section through somite xi, close behind the anterior septum, showing the middle part of the outer ciliated 

 rosette cut through. The other rosettes having been torn were not seen on the section. The spermducts 

 are seen as a small circle, one on either side of the prostate. 



89. Section through the posterior part of somite xi. The outer spermducts are seen as situated farther down, 



approaching each other, the approach being yet closer in the next section. 



90. Section through somite xiv. The prostate being bent zigzag is seen as cut in three different places. At a the 



part anterior to the very narrow pirt or bridge is seen cut. At h this very narrow part and at c the posterior 

 part or storage chamber where the spermducts are seen entering the chamber. 



91. Section through somite xv. The storage chamber is cut close through its anterior ead and is seen surrounded 



by a thick layer of prostate glands. 



92. Cross-section of the atrium below its junction with the prostate, gl. small prostate glands penetrating the outer 



muscular layer, m. s. muscular layer. tube tube winding in the inner layer of fibrous tissue, n. nuclei 

 of lining layer, boundaries of the cells not distinct probably on account of maceration. A few nuclei only are 

 seen in the fibrous mass, which is much thicker in the center surrounding the tube. 



93. Cross-section of the prostate proper in somite xii. <jl. s. small surface glands penetrating between the longi- 



tudinal muscular layer, m.s. longitudinal muscular layer composed of fascicles or plates of .strands, t.m. 

 transverse muscular layer, ijl. c. thick glandular layer of one row of cells. I. ep. lining ep. of cells, spz. 

 spermatozoa. 



94. Cross-section of the narrow part or bridge of the prostate. The layers are the same as in the preceding figure, 



but of difl'ereut relative thicknesses. Letters as in preceding, sp. sperm ducts, out. m. outer layer of 

 muscles, running in different directions. 



95. Cross-section of the storage chamber in somite xv, posterior to the entrance of the spermducts, but very close 



to it. sp. d. spermducts. yl. s. I. large surface or prostate glands. gL.t.s. small surface or prostate glands. 

 ?n. s. longitudinal layer of muscles, t. m. transverse muscles, ep. lining epithelium with large nuclei. 



96. A somewhat oblique section of the posterior part of the bridge, near its junction with the storage chamber, 



but anterior to the entrance of the spermducts, showing the relative size of the layers and the increased 

 epithelium in the anterior part. hr. posterior part of bridge, near its widening, ep. lining epithelium, pr. 

 gl. prostate glands. I. m., t. m. longitudinal and transverse muscular layers, both cut obliquely. Both the 

 transverse muscles and the epithelium are thickened towards one end. 



