478 PROCEEniNCl^ of the NATIO^WL MUSEUM. vol.52. 



PLEUROTROCHA DAPHNICOLA (Thompson). i 



Plate 41, figs. 4-9. 



Proales daphnicola Thompson, Science Gossip, vol. 28, 1892, p. 220, text figure. — 

 Murray, Trans. Royal Soc. Edinburgh, vol. 45, 1906, p. 179, pi. 6, fig. 26. 



fPleurotrocha sigmoidea Skorikov, Trav. Soc. Nat. Kharkow, vol. 30, 1896, p. 284, 

 pi. 7, fig. 8. 



Thompson's original description is very good and there is but 

 little to add to Mr. Myers's figures of the animal, plate 41, 

 figures 4 and 5 ; Thompson calls attention to the ' ' remarkably long " 

 foot glands with "their ducts plainly openmg as projecting tubules 

 at the extremity of the large, swollen toes." At the base of the 

 toe there is a fairly large mucus reservoir. 



Tlie trophi, figures 6 to 9, present an interesting modification 

 of the virgate or "pumping" type. The rami are approximately 

 hemispherical, cuplike structures, functioning as the cylinder of 

 the "pump"; of the usual transverse ridges only the basal one is 

 present, takmg the form of a prominent, hornlike process. On the 

 imier surfaces of the rami, from the tip of the horn to the posterior 

 or dorsal pomt, there is a series of close-set, needlelike teeth, shown 

 in figiu-e 8. These teeth obviously play no part in the mastica- 

 tion of the food, but they explain fully how the animal attaches itself 

 to the skin of worms, as reported by Murray in the paper cited above. 

 The mici rest on the dorsal portions of the rami, in the sinus behind 

 the ventral horn. Each uncus has five teeth, two ventral, pointed, 

 and three dorsal, with rounded, knobhke tips. 



EXPLANATION OF PLATES. 

 Plate 40. 



Fig. 1. Brachionus variabilis, dorsal view; page 475. 



2. Brachionus variabilis, dorsal view. 



3. Brachionus variabilis, dorsal view. 



4. Brachionus variabilis, ventral view. 



5. Brachionus variabilis, lateral view. 



G. Lccane aspasia, dorsal \'iew, page 476. 



7. Lecane aspasia, ventral \'iew. 



8. Lecane aspasia, lateral view. 



~^ Plate 41. 



Fig. 1. Euchlanis plicata, lateral view; page 475. 



2. Euchlanis plicata, dorsal \'iew. 



3. Euchlanis plicata, transverse section of body. 



4. Pleurotrocha daphnicola, lateral view; page 478. 



5. Pleurotrocha daphnicola, dorsal view. 



6. Pleurotrocha dahpnicola, trophi, ventral v-iew. 



7. Pleurotrocha daphnicola, trophi, anterior \dew. 



8. Pleurotrocha daphnicola, internal surface of left ramus. 



9. Pleurotrocha daphnicola, trophi, lateral view. 



1 Note by H. K. Harring, U. S. National Museum. 



