PLATE XVIII 



Fig. 1. Paranemertes caltforjiica Qo&. Transverse section of body a short 

 distance behind brain, showing the two distinct layers of longitudinal muscles 

 (//«and/»i') of body walls separated by a thick layer of parenchyma (/ia>'). 

 Numerous anastomosing bloodvessels {bv) are imbedded in this layer of paren- 

 chyma, as well as in that lying internal to the inner longitudinal muscular layer ; 

 hm, basement layer ; In., lateral nerve ; e, esophagus ; /, integument ; re, rhyn- 

 chocoel. X 30- 



Fig. 2. P. californica. Transverse section of proboscis through basis of 

 central stylet. The section shows the six pouches of accessory stylets symmet- 

 rically arranged between the outer and inner longitudinal muscular layers {ohn 

 and «7;;;). The space between the stylet pouches is closely packed with large 

 gland cells {gl') filled with deeply staining secretion. In the center of the pro- 

 boscis, surrounded by the radially disposed bundles of the inner longitudinal 

 muscles, is a section of the basis of the central stylet (a), and to the right of this 

 a section of the duct i^x) leading from the middle to the anterior chamber of the 

 proboscis ; oef, outer epithelium of proboscis. X 90- 



Fig. 3. P. caliform'ca. Longitudinal, and nearly horizontal, section of body 

 walls in the region of the intestinal csecum, the lateral diverticula of which (/c) 

 are arranged with great regularity in the parenchyma immediately internal to 

 the lateral nerve {In'). A thick layer of parenchyma {far) lies between the 

 diverticula of the intestinal csecum and the muscular walls {Im ' and cm ') of the 

 proboscis sheath ; l>v, blood vessels ; In, lateral nerve ; Im, longitudinal muscles ; 

 cm, circular muscles ; djn, basement layer ; /, integument. X 30- 



Figs. 4, 5. P. californica. Central stylets and bases (see pi. xxi, figs. 3-9). 



X90- 



Fig. 6. T^niosoma punneiti Coq. Lateral view of anterior portion of body 

 after clearing in cedar oil, showing distribution of the numerous small ocelli 

 immediately ventral to dark marking on snout, which is marked off from suc- 

 ceeding portion of head by an annular constrictiono The mouth {m) is indicated. 

 X8. 



(212) 



