1^8 ART. 4. — I. IKEDA : 



The longitudinal muscles are divided into separate, but very 

 frequently anastomosing, bundles ; in the region of the segmental 

 organs they are 16 in number and in the posterior region of 

 the body about 22. The retractor muscles (Fig. 58) occur in a 

 single ventral pair, the dorsal pair being Avanting. The pair 

 present are attached to the body-wall at the beginning of the 

 posterior third of the body proper. The intestinal convolution 

 consists of about 15 double spirals, twisted around the spindle- 

 muscle {sm) which is fixed at its posterior end. The intestine 

 is suspended by two fixing muscles (fin), both of which lie to 

 the left of the nerve-cord [n) ; one of them arises just behind 

 the root of the left retractor muscle, and is joined to the pos- 

 terior part of the intestinal convolution, while the other arises 

 at a point of the body-wall about 7 /ii/it. in front of the origin 

 of the first and ends at the first spiral. There is no blind 

 diverticulum on the rectum. The anus (a) is situated near the 

 anterior end of the body proper, at the same level as the ex- 

 ternal apertures of the segmental organs. These (so) are long, 

 being nearly half as long as the body proper ; throughout their 

 whole length they are attached to the body-wall by a thin mes- 

 entery. The contractile villi of the dorsal vessel are very 

 numerous and tolerably long, reaching up to 2 uini. in length ; 

 some of them show a slight ramification. 



The most remai'kable characters of the species consist (1) 

 in the total absence of hooks and (2) in the retractor muscles 

 being present in a single pair. No form combining these two 

 characters seems to have been hitherto recorded. 



Habitat : The sandy shore of the Inlet of Onomichi in 

 the Inland Sea. 



