HOLOTRICHA 



597 



P. minuta Powers (Fig. 282, 6). 50-75m by 36-46m; in the intestine 

 of Strongylocentrotus droehachiensis; the Bay of Fundy. 



Genus Lechriopyla Lynch. Similar to Plagiopyla; but with a large 

 internal organella, furcula, embracing the vestibule from right, and 

 a large crescentic motorium at left end of peristome; in the intestine 

 of sea-urchins. 



Fig. 282. a, Plagiopyla nasuta, X340 (Kahl); b, P. mimda, X400 

 (Powers); c, Lechriopyla niystax, X340 (Lynch); d, Sonderia pharyngea, 

 X590 (Kirby); e, S. vorax, X310 (Kahl); f, Clathrostoma viniinale, X220 

 (Penard); g, Physalophrya spumosa, X160 (Penard). 



L. mystax L. (Fig. 282, c). 113-174ju long; in the gut of Strongylo- 

 centrotus purpuratus and S. franciscanus; California. 



Genus Sonderia Kahl. Similar to Plagiopyla in general appear- 

 ance; ellipsoid; flattened; peristome small and varied; body covered 

 by 2-4;u thick gelatinous envelope which regulates osmosis, since no 

 contractile vacuole occurs (Kahl); with or without a striped band; 

 trichocysts slanting posteriorly; in salt or brackish water. Kirby 

 (1934) showed that several species of the genus are common in the 



