ONUPHIS LITABRANCHIA. 275 



wholly complete, has an aggregate length of about 167 mm., and a second com- 

 plete but similarly broken specimen has nearly the same length (1G5 mm.). 

 The greatest width, exclusive of the parapodia, is only 2 mm., the depth varying 

 from 1 to 1.5 mm. The total number of somites counted in the fragments of 

 the type is two hundred and twelve, the number in a paratype two hundred 

 fifty, or above. 



The general color is yellow, the sides, including parapodia and cirri, paler 

 and the nerve cord showing as a narrow, white, median ventral line sometimes 

 appearing broken into spots corresponding to the ganglia. 



The prostomium small, very short proximally, subcyUndrical, its outline 

 in anterior view nearly circular, but with lower part of circumference some- 

 what flattened. Its surface is largely occupied by the bases of the seven tenta- 

 cles which are arranged in a circle. The surface encircled by the bases of the 

 tentacles is indented or depressed, the impression being more or less transverse, 

 and the surface below this region protruding forward and bearing the frontal 

 tentacles. The frontal tentacles are very short, broad, flattened dorsoventrally 

 and distally subtruncate, or with distal edge a little incurved. They widen from 

 the base distad, being prolonged distoectally. At the base they are only very 

 narrowly separated, nearly contiguous. The dorsal tentacles all have long 

 stout ceratophores bearing very slender, distally finely attenuated styles. 

 The ceratophores are essentially smooth, only in part obscurely wrinkled and 

 not obviously articulate. The tentacles of the anterior pair reach to or some- 

 what beyond the middle of somite III. In these the style is nearly twice as 

 long as the ceratophore; it is rather abruptly thickened at the base in contact 

 with the ceratophore. Tentacles of the posterior pair reaching somite IX. 

 In these the ceratophore is decidedly longer than that of the anterior. The 

 style is similarly enlarged proximally and is more than three times as long as 

 the ceratophore. The median tentacle reaches upon somite III, or nearly to 

 IV, being of essentially the same size as the anterior paired ones, with cerato- 

 phore and style of similar form and proportions. The enlarged proximal ends 

 of the styles are lighter in color, whitish. (Plate 51, fig. 1). 



Peristomium distinctly wider and higher than the prostomium, bulging 

 smoothly outward and upward from its line of contact with the latter. It is only 

 weakly produced forwards at the sides. Dorsally there is a low median longi- 

 tudinal ridge which at its anterior end projects as a low triangular process against 

 the prostomium, a sulcus running from the tip of the triangle on the prostomium 

 to the base of the median tentacle. The lower lip is set off on each side by a 



