688 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Family Horneridae Smitt, 1867 



The zoarium is erect, branching like a tree, with rounded stems and 

 branches ; the zoids opening on the frontal side only ; the inflation of the 

 gonozoid or ovicell on the dorsal side of the zoarium. The family has 

 not hitherto been recorded from the Pacific coast of America. 



Genus HORNER A Lamouroux, 1821 



With the characters of the family. Genotype, Hornera frondiculata 

 Lamouroux, 1821. The zoarium with a moderate encrusting base, an 

 erect round stem which branches like a tree with the successive branches 

 diminishing in diameter, and the zooecia all opening on one side, easily 

 distinguish the genus. The species are usually highly colored red or 

 purple. 



Hornera pectinata Busk, 1861 

 Plate 72, figs. 10, 11, and 12 



Hornera pectinata Busk, 1861:79; 1875:18. 

 Hornera pectinata, Johnson, 1897:61. 

 Hornera pectinata, Norman, 1909:280. 



The zoarium is erect, flabellate, the short main stem rising from a 

 slightly expanded base; height 25 mm; the base measures 5 by 7 mm, 

 the main stem 3 mm, the larger branches about 2 mm, the terminal 

 branches just below the tips 0.50 to 0.60 mm. The branching is in one 

 plane, irregular with a tendency toward dichotomy; the main branches 

 are rather regularly tapered from base to tip ; all of the branches are 

 round even in the youngest stages. Stunted branches rare. Apparently 

 purple when living. 



The zooecia are irregularly arranged in more or less transverse rows 

 of 2 to 4 tubules, connate or separated and often single. All of the 

 peristomes are short, but the outer ones are slightly longer. On older 

 branches the apertures are nearly level with the surface, the apertures 

 round, 0.20 to 0.24 mm in diameter, the rim of the peristome thin, often 

 slightly flared and delicately serrate (never incised), the points being 

 the tips of the parallel ridges or thickenings of the peristome. The longest 

 marginal peristomes are seldom as much as 0.20 mm in height. The 

 sulci are strongly developed on both frontal and dorsal sides and the 

 pores are round or slightly elongate. The ridges between the sulci are 

 very irregular on the frontal surface, but are continuous and more or 

 less parallel on the dorsal side. Complete calcification of the zoarium 



