[IJ ALRXANDROMENIA VALID A. 



Tlio colls of the posterior pedal gland are of comparatively small size, but 

 otherwise are essentially tli(> same as those of the anterior pedal gland. As 

 usual they open by separate intercellular exits into.the pedal furrow. 



In several sp(>cies of Solenogastres the foot is accompanied by two longi- 

 tudinal ri(lg(-s, modifications of the hypodermis. In the present species the 

 median projection is bordered by two pi'ominences on each side. All are of 

 essentially the same size and appearance, being thin folds of epithelium into 

 wliicii a few muscle antl connective-tissue fibres project. No blood spaces 

 occur within tiiem and at their bases the secretion from the pedal gland finds 

 its outlet. 



The atrial cavity in the only specimen examined is of limited extent (Plate 11, 

 fig. '.i), but it possesses ridges of large size that together with the cirrose area 

 presents a very characteristic appearance. The indistinct prominence, which 

 in some species accompanies the outer ridge, is not sharply defined, being recog- 

 nizul)le solely by the rod-like group of ganglion cells in the customary position. 

 The outer atrial ridge projier is of large size, and as a much folded, horseshoe- 

 shaped elevation surrounds the atrial cavity except posteriorly. The inner 

 fold is of inferior size and consists of two ridges which arise independently on 

 the roof and posteriorly diminish in size and gradually disappear. Their epi- 

 thelial covering consists of high slender cells with elongated subcentrally placed 

 nuclei distal to which the cytoplasm contains quantities of light yellow pigment. 

 Internally the folds are sujiported by strands of connective tissue with a sriiall 

 adniixtiu'e of muscle f Hires among which well-defined l)Iood sinuses pursue their 

 course. 



The cirri arise singly from the atrial wall and are of more than ordinary 

 thickness. As usual each consists of an outgrowth of the buccal wall, composed 

 of more or less cubical cells in which the yellowish brown pigment is so abundant 

 that it usually conceals the nucleus. The cavity of each cirrus is very narrow, 

 allowing the passage of a nerve strand l)ut not of the blood. 



The liuccal cavity or jiharynx, seixirated from the atiial cavity by a circular 

 fold (I'late 11, lig. 3), is an irregular cavity whose general appearance and rela- 

 tions are represented in Thite 21. The walls throughout are produced into 

 numerous wavy, more or Ic-ss longitudinal folds, lined with a thin cuticular sheet. 

 In the middle third, whicli contains the radula, the folds become more distinctly 

 longitudinal, but moi-e posteriorly they once more become very irregular. 



As ni .1. (ifidsxizl there are three sets of salivary glands, and as may be seen 

 ni I'late 21, figs. 2, 4, in arrangement and size, they are essentially the same as 



