1904.] NATURAL SCIENCES OF PHILADELPHIA. . 173 



They about equal or exceed the body diameter, are strongly directed 

 ventrad, and for the greater part of their length they are gently, and 

 near the tip more sharply, curved; and here are also flattened and 

 provided with a delicate wing, beyond which they taper to an acute 

 point. 



The tori of somite III contain about 90 uncini and more posterior 

 thoracic somites a much greater number. They are rather large trape- 

 zoidal plates (fig. 32), coarsely striated transversely. The pecti- 

 nate margin bears 14 or occasionally 13 acute teeth, of which the 4th, 

 5th and 6th are the largest, the upper ones becoming shorter and the 

 lower or cephalic ones especially more slender, the former more hooked, 

 and the latter straighter but more imbricated and appressed, and the 

 last 2 or 3 successively wider, flatter and more curved in the trans- 

 verse plane. The last tooth is much larger, tubular and truncate, and 

 in man}^ cases is more or less closely embraced by the preceding one. 

 The anterior abdominal tori bear about 20, the caudal ones as many as 

 50 uncini (fig. 19), which are only about h as long and much more deli- 

 cate than the thoracic ones which they resemble closely in form. 

 The apical offset from the plate is more prominent, the number of teeth 

 usually 13 or sometimes 12, and the truncate tooth is more closely 

 embraced by the one next to it than in the thoracic uncini. 



Fragments of the tube are 3.5 mm. in diameter at the mouth, 2 mm. 

 in diameter at a distance of 30 mm. from the mouth. Externally they are 

 marked by a series of wide flaring flanges, sometimes completely encir- 

 cling the tube, sometimes coalescent with it or incomplete on one side. 

 The surface is marked by a varying number of delicate but rough, 

 undulating parallel longitudinal ridges about .7 mm. apart, the number 

 being usually limited to about 6, confined to one, but not always the 

 same, side. On the free flaring portions of the flanges these ridges 

 become broken into flat spines, many of which are arranged trans- 

 versely. 



Suruga Bay, 3,713, 45 fms., type and portions of tube. 

 Pomatostegus latiscapus Marenzeller. 



Two specimens of a Pomatostegus agree closely with Marenzeller's 

 description of all parts except perhaps the collar, concerning which it 

 is simply stated that it is produced directly forward and has no lateral 

 incisions. In the Albatross specimens the collar has a very irregular 

 and ragged border, with a long median ventral process and somewhat 

 smaller dorso-lateral processes at the level of the setse; but no actual 

 incisions. The setse and operculum agree perfectly. In one specimen 

 the operculum bears 4, in the other 7 platforms, and in the latter 



