PLATE X. 



Mesenchytrceus beringensis sp. nov. 



FIG. x. Spermatheca. Side view. One spermatheca is seen entire. Of the 

 other only the junction with the intestine is shown. 



2. Transverse section of the body in somite xn, passing through the 

 sperm-ducts and the male-pores. The penial bulb is seen to con- 

 tain large penial glands, while the absence of accessory and atrial 

 glands is prominently characteristic, p.ck., penial chamber; f., 

 funnels; P-gl-> penial glands; sp.d., sperm-ducts. 



3. Section passing through the male-pore and papilla ; from a trans- 

 verse section of the body, p.b., penial bulb; p.ck., penial chamber 

 or lower part of sperm-duct; p.gl., penial glands, opening around 

 the pores and entirely confined inside the penial bulb; atr., atrium 

 of the sperm-duct. The penial chamber is enclosed in a sheath of 

 circular muscles. A few intra-penial glands open around the pore. 



(146) 



