274 THE ANNELIDA POLYCHAETA. 



one at the proximal end of the series, or a total of ten. The right maxilla III 

 is a strongly curved plate presenting a sleiider, straight, edentate arm extending 

 proximad and a curved distal portion bearing a series of nine teeth. The 

 right maxilla IV is a triangular plate in which the anteromesal corner is acute 

 and is turned up as a tooth-like process. (Plate 43, fig. 8). The left maxillae 

 are injiored and partly missing, so that their description cannot be given. The 

 mandibles are small, unusually thin, membranous and flexible, and in general 

 weakly developed; anterior margins meeting at an obtuse angle, smooth and 

 straight; stems weak. 



Locality. Gulf of Cahfornia: Sta. 3431 (lat. 23° 59' N., long. 108° 40' W.). 

 Depth 995 fms. Bottom of light brown mud. Bottom temp. 37° F. 20 April, 

 1891. One specimen. 



This species seems to approach 0. vexillaria Moore, dredged by the Alba- 

 tross off the southern Californian coast at two stations at depths of 243 to 280 

 fms. (Sta. 4326 and 4401). It is a more robust species with the somites shorter 

 in proportion to length. The branchiae begin on the fifth parapodia instead 

 of on the fourth. The maximum number of branchial filaments is smaller, 

 being six instead of twelve, and the branchiae remain branched as far back as 

 somite CXIX, whereas in vexillaria they have already become unifilar in front 

 of L. The tentacles are longer, the posterior laterals, e.g., reaching somite 

 XVII instead of only to X. In vexillaria the median tentacle is shorter than the 

 posterior laterals, with the ceratophore also clearly shorter, whereas in the 

 present species the median tentacle is longer than these laterals with the cera- 

 tophore equally long. The right maxilla III in the present species has nine 

 teeth as against six in vexillaria. The compound crochets have essentially the 

 same structvire ; but in the ordinary crochets the apical tooth is distinctly longer 

 and more erect and the guard is clearly differently shaped. The distal edge of 

 the pectinate setae is much less oblique. 



Onuphis litabranchia, sp. nov.^ 



Plate 50, fig. 7; Plate 51, fig. 1-10; Plate 52, fig. 1. 



This is a very slender and elongate species which is flattened dorsoventrally 

 and is of nearly uniform width except at the ends where it narrows cephalad 

 and caudad respectively. The type, which is broken into six pieces and is not 



' \lTb^, simple, and [ipayix<^, gills. 



