683 PROCEEDIjS^GS of the national museum. vol. XXXV. 



Station 4429, Gull Island N. 21° W. 2.9 miles, 506-680 fathoms; Sta- 

 tion 4461, Point Pinos light-house S. 3° E. 9.3 miles, 285-323 fathoms. 

 This striking species is named in honor of Prof. William E. Ritter, 

 of the University of California. 



Order PENNATULACEA. 



Cofony free, consisting of a central stem, bearing polyps on its 

 distal portion. Polyps either sessile, or borne on lateral leaves. A 

 horny axis usually present. In addition to the polyps, zooids are 

 usually found in this group. 



Family PENNATULID^. 



Colony in the form of a true feather, leaves or pinnules large and 

 evident. 



Genus PENNATULA. 



Zooids on the ventral side of the rachis only. Spicules scattered 

 over the entire surface, not confined to the borders of the leaves. 



PENNATULA ACULEATA Danielssen. 



Pennatula aculeata Danielssen, Forh. Vid.-Sel., Christiania, 1858, p. 25. 



Numerous specimens collected by the Fisheries steamer Albatross 

 seem to be of this exceedingly variable species. The following is a 

 description of a typical colony : 



Total length of colony 119 mm.; length of stem 45 mm. Stem 

 distinctly swollen just below the rachis, the fleshy part abruptly 

 pinching out about 7 mm. from the end, leaving bare the horny axis 

 which expands into a terminal, transparent, greatly flattened knob 

 or club. This is probably due to- mutilation. 



Leaves 23 pairs, the longest 17 mm. long by 3.5 broad, closely 

 approximated. 



There are about 10 calyces to each full grown leaf, their margins 

 being surmounted by 8 slender acute points formed mainly by con- 

 verging spicules. 



Zooids densely crowded on the ventro-lateral surface, leaving a 

 broad median band bare. Each zooid is guarded by a stockade of 

 5 to 10 spicules on its proximal side. 



Spicules of the usual pennatulid type, the longest forming the 

 calycular teeth and along the lower edges of the leaves, where they 

 furnish a stiff support. They also form longitudinal bands between 

 adjacent polyps, marking the surface of the leaf. 



Color. — Zooids deep carmine red, pinnse yellow, streaked closely 

 with crimson. Stem and bare portion of rachis dull brownish 

 yellow. The general efl^ect is a dull crimson for the colony as a 

 whole. 



