DRIOMENIA PACIFIC A. 93 



The paired gonad extends forward to a point slightly behind the level of 

 the hinder end of the radula supports. Anteriorly its cells are entirely male, 

 minute ova appearing only in the most posterior part of the fragment. 



Driomenia pacifica, sp. nov. 



Three individuals of this species were taken off the southern end of Japan, 

 two from Ose Zaki (Sta. 3716) at a depth of 65-125 fms. and one from Kago- 

 shima Ciulf (t^ta. 4935) at a depth of 103 fathoms. All were imbedded in a mass 

 of hydroids belonging to the genus Sertularella. The body is of uniform diam- 

 eter, measuring 1 mm. by 9 mm. in length. The color in alcohol was a yellowish 

 white. 



No dorso-terminal sense organ has been discovered. 



The cuticle is thick and contains an innumerable number of hollow spicules 

 of varying sizes but with the general form represented in Plate 39, fig. 5. The 

 usual hypodermal cells are not especially favorable for stud}', but on the other 

 hand those of the papillae (Plate 38, fig. 10) are exceptionally clear. In the distal 

 portion of each i)apilla the cells are spindle shaped, usually compact and finely 

 granular, and appear in many cases at least to be continuous with a slender 

 fibre which traverses the stalk and may be followed readily into the tissue beneath 

 the hypodermal layer. Beyond this point their course cannot be determined 

 with certainty and accordingly there is no clear evidence as to whether they are 

 muscle or nerve. 



The anterior pedal gland, occupying the customary position, is composed 

 of the usual pyriform cells of average size. Posteriorly it passes without any 

 change, except a decrease in the number of cells, into the posterior pedal gland 

 which accompanies the foot throughout its entire extent. The outlet of the 

 anterior pedal gland (Plate 38, fig. 1) is a plain walled, globular cavity heavily 

 ciliated. Posteriorly two lateral and one median fold arise on its walls and soon 

 unite to form the foot which continues to the cloacal opening though the two 

 lateral folds become of small size. 



The atrial chamber, distinctly separated from the remainder of the digestive 

 tract bj' a spiculose ridge, is a cavity with walls fashioned into the usual sensory 

 organs. The inner and outer ridges are moderately low, horseshoe-shaped 

 ciliated folds nearly encircling the chamber and bounding the cirrose area. Each 

 cirrus is very slender, without a distinct cavitj' and is usually united at its base 

 with one or two others. 



The true mouth opening is borne on the summit of a low yet broad pro- 

 boscis which is separated by a very narrow spiculose ridge from the outlet of 



