ADDITION TO POLYCHAETOUS ANNELIDS 189 



Family HESIONIDAE 



Genus HESIONE Savigny 



HESIONE GENETTA Grube 



Hesione genetta Grube, Jahresbericht der natur. Sect, der Schles. Gesellsch., 

 1866, p. 63; Annulata Semperiana, Mem. Akad. Imp. Sci. St. Petersbourg, 

 vol. 25, no. 8, 1878, p. 104 : 



One specimen, collected in tide pool on Tobea Island. 



Family NEREIDAE 

 Genus NEREIS Linnaeus 



NEREIS MASALACENSIS Grube 



Figures 13 to 17 



Nereis masalacensis Grube, Annulata Semperiaua, Mem. Akad. Imp. Sci. 

 St. Petersburg, vol. 25, no. 8, 1S78, p. 75, pi. 5, fig. 4. 



On the assumption that the paragnath and tooth formula does 

 not change in assuming the heteronereis phase, I have assigned to this 

 species of Grube's a considerable number of heteronereids collected 

 at Varadera Bay, Mindanao, identification being aided by some other 

 points of agreement with Grube's description. Lateral brown streaks 

 of pigment in anterior somites occur in the heteronereids as well as 

 in the original material. 



The prostomium (fig. 13) is nearly rectangular in outline, the 

 middle half of the anterior margin being extended to form the ten- 

 tacle bases. What are evidently the eyes appear as slight elevations 

 on the lateral margins of the prostomium though because of a dense 

 accumulation of pigment they are not definitely visible. This pig- 

 ment is a dense purple in color, and except for a narrow median line 

 on the dorsum extends over the entire dorsal surface of the pros- 

 tomium, leaving the tentacles uncolored. The basal portion of the 

 palp is uncolored, but its apex is pigmented, though of a lighter 

 color than the prostomium. 



In the specimen figured the protruded pharynx distorts the peris- 

 tomium. In another this is seen to be distinctly biannular, and much 

 shorter dorsally than ventrally. A rounded nuchal lobe extends 

 from its anterior border over the posterior end of the prostomium. 

 The peristomium is pigmented and each of the following 13 somites 

 has on either side a pigment spot whose size becomes smaller suc- 

 cessively from somite to somite. The postero-dorsal is the longest 

 of the tentacular cirri, its apex in the male reaching to the twentieth 

 somite or the end of the anterior body region. 



