92 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



extended enough to give complete measurements. When extended 

 the body is elongate, about four and one-half times longer than wide, 

 flattened, and without spines or special skin glands. It is evenly 

 rounded posteriorly and anteriorly. One extended specimen measured 

 8.795 mm. in length and 1.993 mm. in width, the widest portion 

 being near the posterior end of the body. Near the anterior end is 

 a collar in the form of a muscular ridge which is comparatively weak 

 when contrasted with this structure in other genera of the subfamily. 

 It is interrupted ventrally by a concave, oval depression which occu- 

 pies the median half of the ventral surface of the anterior third of 

 the body. When contracted the body is boat shaped (fig. 3). The 

 anterior ventral depression then seems to extend the entire length 

 of the worm. A contracted specimen measured 6.629 mm. in length. 

 The body is highly muscular with an abundant concentration of 

 transverse bundles in the anterior region, especially in the region of 

 the ventral depression. 



The oral sucker measures 0.6 mm. in width and 0.57 mm. in 

 length. The esophagus is slender with an expanded anterior portion, 

 and measures 0.375 mm. in length. The ceca are narrow and extend 

 nearly to the posterior end of the body, bowing medianly in the 

 region of the testes. The walls of the ceca are irregular with small 

 outpocketings hardly long enough to be considered branches. 



The testes are large and strongly lobed, lying opposite each other 

 near the posterior end of the body. The intestinal ceca pass between 

 the testes and overlap the inner margins of them ventrally. Each 

 testis is divided into about seven large lobes, some of which may be 

 subdivided to form secondary lobes. The tubular seminal vesicle is 

 voluminous, lying free in the parenchyma, passing from the posterior 

 fourth of the body to the posterior portion of the large cirrus sac 

 located about at mid-body. The extreme posterior portion of the 

 vesicle is straight but as it passes anteriorly it becomes coiled. The 

 cirrus sac is large and divided by a constriction into two parts which 

 form an angle of ninety degrees with each other. The posterior half 

 of the sac passes diagonally forward from the seminal vesicle 

 to the inner edge of the right cecum. The anterior half of the sac 

 returns to the mid-line and genital pore (fig. 1). The prostatic por- 

 tion of the cirrus sac occupies about nine tenths of the whole sac and 

 is made up of large cells which appear to project into the central 

 lumen. The cirrus is in the form of a muscular papilla projecting 



