284 AETHUR E. SHIPLEY. 



specimens. It consists in the more typical form of a 

 number of large^ more or less cubical cells^ full of a densely 

 granular protoplasm. The cells take every variety of shape, 

 owing to mutual pressure and the various strains and stresses 

 which affect them. In life their outline cannot remain 

 constant for any length of time. In the more poorly pre- 

 served specimens the granular protoplasm had shrunk away 

 from the firmer exterior of all but one surface of the cell, 

 leaving a large but irregular vacuole. The firm external 

 part of the cell, with from time to time patches of contracted 

 protoplasm adhering to it, gives the parenchyma the appear- 

 ance of a network with considerable vacuoles. When this 

 firmer exterior is a little more emphasised it forms the base- 

 ment membrane, which undei'lies the ectoderm and surrounds 

 the various parts of the reproductive system ; it is, however, 

 very noteworthy that no such basement membrane surrounds 

 the alimentary canal or intestine. 



The Digestive System. — The mouth is ventral, in the 

 middle line and situated about the distance of one eighth or 

 one tenth of the body-length from the anterior end of the 

 body (fig. 4). It leads by a very short passage, lined by 

 cuticle, and bearing as far as I could make out no glands of 

 any sort, into a spherical pharynx. This organ is of the 

 type found in Vortex or Plagiostoma. The minute lumen 

 is lined by a uniform cuticle, and the bulk of the thick 

 wall is built up of radial muscle-fibres, among which a few 

 large nuclei stand out in stained sections (fig. 7). From the 

 inner end of the pharynx a very short oesophagus provided 

 with numerous glands — the so-called salivary glands — leads 

 to the digestive sac. 



The stomach or intestine, or, as I prefer to call it, the 

 digestive sac, is a rod-like organ extending along the middle 

 line of the animal, and so close to the dorsal surface that 

 there is practically none of the parenchymatous tissue which 

 serves as a packing for the various organs of the body be- 

 tween it and the epidermis (fig. 2). The axis of the lumen of 

 the mouth, pharynx, and oesophagus is a dorso-veutral one, but 



