chamberlin: pacific coast polychaeta. 257 



larger than those of the more posterior series. Each maxilla with six teeth. 

 Number of segments, seventy. 



Length, 33 mm. ; greatest width, exclusive of parapodia, 3 mm. 

 Locality. — CaHf. : Mendocino (A, Agassiz). 

 Type.— M. C. Z. 2,129. 



15. Nereis agassizi Ehlers. 



Borstenwiirmer, 1868, p. 542, pi. 23, fig. 1. 



Mendocino, Calif. (A. Agassiz). 

 Type.— M. C. Z. 149. 



Leodicidae. 



16. Leodice valens, sp. nov. 



Plate 1, fig. 6-8. 



In the type of this species the branchiae begin on somite V and end on 

 somite LXXX on the right side and LXXVIII on the left. The first and 

 second branchiae are simple filaments; the third are bifid with the two fila- 

 ments equal; the fourth gills, like the succeeding compound ones, unilaterally 

 pectinate, the branches five in number, each forming an acute angle with 

 base. Caudad of this the number of branches increases to a maximum of 

 ten, the branchiae also longer, when laid against dorsum attaining or extending 

 a little beyond the mid-dorsal line. Farther back they again decrease in 

 length and in number of filaments, and the last seven to nine are simple fila- 

 ments like those of the first two pairs. Anterior border of prostomium emar- 

 ginate or incised at the middle between bases of palpi. Anterior lateral ten- 

 tacle on each side inserted cephaloectad of the posterior and directly in front 

 of the eye. Posterior paired tentacle a little farther forward than the median, 

 the bases of all forming a semicircle. Ceratophores extremely low. Style 

 of median tentacle evenly tapered, not constricted between rings which are 

 cylindrical, long, and about twelve in number. Nuchal cirri nearly reaching 

 anterior edge of peristomium; rings eight or nine, not at all moniliform. 

 Mandibles with anterior plates white, anterior margin of each with two incurv- 

 ings and three rounded teeth or broad crenulations. Left maxilla II with six 

 teeth; the right with eight of which the most caudal are small; the unpaired 

 or mesal left plate with eight (or nine) teeth. Left maxilla III with six teeth, 

 the right with eight. Notocirri mostly flattened subligulate; the anterior 



