1906.] NATURAL SCIENCES OF PHILADELPHIA. 255 



Both specimens come from Station 4,197, Gulf of Georgia, 31 to 90 

 fathoms, sticky green mud and fine sand. 



Amphicteis scaphobranchiata sp. nov. Plate XII, figs. 54-61. 



A single well-preserved specimen represents this noteworthy species. 

 The length without branchiae is 32 mm., the branchiae 7 mm., and the 

 maximum '\\ddth in the anterior part of the thorax 2.8 mm. 



The anterior lobe of the prostomium (fig. 54) is almost completely 

 divided by a longitudinal fiu-row into a pair of somewhat slender 

 tentacle-like divisions which are somewhat divergent anteriorly. A 

 narrow transverse welt passes across the base of this region and is 

 partly concealed by the much larger and more prominent sensory 

 folds which lie behind it. These pass from the lateral borders of the 

 head nearly transversely to the middle line, where they meet in a wide 

 angle. Laterally they are continuous with the lateral lobes or folds 

 which join the frontal lobe beneath. The tentacular membrane lies 

 below the frontal and lateral lobes and is partly embraced by the 

 peristomium. It bears from twelve to fifteen tentacles on each side, 

 the lateral ones being very short and the middle ones as much as two- 

 thirds the width of the thorax. All and especially the shorter ones 

 are more or less clavate. 



The prostomium passes without any clear demarkation into the 

 peristomium, which reaches as a smooth unbroken convex surface to 

 the branchial segment. Dorsally it is remarkable for its extent, 

 smoothness and absence of furrows. Its length and breadth are each 

 equal to about two-thirds of the width of the branchial segment. In 

 the middle line it reaches to the interbranchial shield, but its postero- 

 lateral angles are cut off by the paleolar tubercles and lateral portions 

 of somite II. Ventrally the peristomium forms a large, broadly trun- 

 cated lower lip, slightly inserted into II and embraced laterally by the 

 paleolar tubercles. 



The second somite is more than half as long ventrally as the peristo- 

 mium, but except for the narrow strip extending dorsally beneath the 

 branchiae it ends abruptly at the enlarged paleolar tubercles. Somite 

 III is very short and IV slightly longer, the two combined just equalling 

 the length of II. Behind this region the segments again diminish in 

 both length and diameter to the pygidium. With the exception of 

 the last three or four, the thoracic segments are ill defined on the ven- 

 tral and not at all on the dorsal side. Up to the level of the setae tufts, 

 where a lateral shelf -like ridge is formed, the body walls are rather 

 thick and firm, with slight anterior glandular bands and obscure 

 ventral plates. Dorsal to the setae the body for the entire length is 



