1923] NATURAL SCIENCES OF PHILADELPHIA 213 



The setse, uuciui (Plate XVll, fig. 25) and other characters agree 

 with M. cristata. 



Length of available specimens 23 to 90 mm. 



A number of tu])es measure 130 mm. long and 3 mm. in diame- 

 ter and have the typical form and structure. 



The differences between this form and typical M. cristata are 

 constant but so slight that it is designated as a subspecies. While 

 generally a deep water form it has a remarkable bathymetric 

 range of over 2000 fathoms. 



Stations 4322, off Point LaJolla, 110-199 fathoms, soft green 

 mud; 4325, 191-292 fathoms, green mud and fine sand; 4396, lat. 

 33° 01' 35" N. long. 121° 28' 30" W, 2228 fathoms, red mud; 4415, 

 off Santa Barbara Island, 302-638 fathoms, green mud; 4433, off 

 Santa Rosa Island, 243-265 fathoms, green mud; 4517, off Point 

 Pinos Lighthouse, 750-766 fathoms, green mud and sand; 4537; 

 same locality 1006-1041 fathoms, hard sand and mud; 4541, same 

 locality, 381-633 fathoms, green mud and sand; 4546, same locality, 

 849 fathoms, fine black sand (27 specimens, including type and 

 cotypcs); 4574, lat. 30° 35' N., long. 117° 24' W., 1400 fathoms. 



Melinna denticulata Moon;. 



The original description is in error in describing as the lower 

 lip the inferior flange or collar of somite II into which the prosto- 

 mium and ventral portion of the pcristomium are retractile. The 

 post-branchial membrane of each of the three specimens bears 

 seven or eight minute teeth. An even more o])vious distinction 

 between this species and M. cristata is that the former has seventeen, 

 the latter eighteen thoracic setigerous somites. The branchiae also 

 differ and the thoracic uncini of M. denticulata have the superior 

 teeth more ro])ust and the inferior teeth longer. The nuchal 

 hooks are straighter and more tapering than in most species. 



An incomplete tube is 2.5-3.5 mm. in diameter, with a thin 

 membranous lining and a thick, very fragile covering of fine silt 

 containing numerous small scales of mica i)lace(l transversely to 

 the axis of the tube. 



Stations 4351, oft' Point Loma Lighthouse, 423-488 fathoms, 

 soft green mud; 4352, same locality, 549-585 fathoms, green mud; 

 4365, same locality 130-158 fathoms, green mud. 

 Melinna pacifica Mcintosh. 



The collection includes more than forty specimens and a number 

 of tubes from Station 4436, and three from Station 4390. Fn- 



