NO. 5 ERASER : HYDROIDS 261 



Distribution. — Tyler Point, San Miguel Island, shore; Santa Cruz 

 Channel, 32-34 fathoms ; off Redondo Beach, Calif. ; off San Pedro break- 

 water, 4 fathoms; off Huntington Beach, 10 fathoms; 5 miles — 152° 

 from San Pedro breakwater, 17-19 fathoms; west of Dutch Harbor, San 

 Nicolas Island, 8-9 fathoms; San Quentin Bay, Lower Calif., 8-9 fath- 

 oms; Rosario Bay, 10-15 fathoms. 



Aglaophenia triplex, new species 

 Plate 32, Fig. 29 



Trophosonie. — Colonies grow in clusters to a height of 8 cm; they 

 are quite symmetrical but the plume is tapered farther and more gradu- 

 ally than is common in the genus. The stem is not a very dark horn color 

 but it is much darker than the hydrocladia. Nodes are indicated but are 

 not strongly marked. The hydrocladia are fronto-laterally placed, in reg- 

 ular alternation ; the processes on the two sides are at an angle of nearly 

 90° to each other; from the process the hydrocladium curves outward, 

 and continues to do so ; in consequence, the plume does not appear as a 

 plane surface. The nodes of the hydrocladium are indistinct or absent, 

 but in what corresponds to an internode, there are 2 partial septa, 1 at the 

 base of the supracalycine nematophore, and the other opposite the hydro- 

 thecal septum. The hydrotheca is of medium length and width, not pro- 

 jecting outward strongly. The intrathecal septum is well marked, reaches 

 about half way across the hydrotheca, and is curved, the concave side fac- 

 ing towards the margin. The teeth on the margin provide the special fea- 

 ture; there are 9 of them. Instead of having a single median tooth, there 

 are 3 much similar, small, sharp-pointed teeth, forming nearly a straight 

 line across the face of the hydrotheca; the 3 on each side that are truly 

 lateral, are much larger than each of these frontal teeth ; they are rounded 

 and similar; the first of these projects forward so well that, in a direct, 

 lateral view, the frontal teeth are entirely hidden. Of the 3 groups of 3 

 teeth, those in the 2 lateral groups, similar in themselves, are quite differ- 

 ent to those in the frontal group. The supracalycine nematophores are 

 large, overtopping the margin of the hydrotheca ; the mesial nematophore 

 is only slightly shorter than the face of the hydrotheca, with but a small 

 portion projecting. The 3 cauline nematophores on each internode are of 

 less than medium size. 



Gonosome. — Not observed. 



Distribution. — Station 1075-40, inside Georges Island, near the head 

 of the Gulf of California, W/z-lZ fathoms. 



