134 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



Scrupocellaria bertholetti var. tenuirostris new variety 

 Plates 18, fig. 8, and 21, fig. 6 



The zoarium is erect, but rather loose and spreading, growing among 

 hydroids, algae and other bryozoans, reaching a height of about 20 mm. 

 Usually there are either 5 or 7 zooecia in an internode and the joint 

 crosses the outer primary zooecium of a branch at the proximal end of 

 the opesia, the inner zooecium below the opesia. 



The zooecia are quite regular in size and form (length 0.40 mm to 

 0.45 mm, width 0.20 at the widest part and 0.10 at the proximal end), 

 the outer margin nearly straight. The opesia is elliptical or slightly nar- 

 rowed proximally, about three-fourths as long as the zooecial front. 

 Spines 3 (2 to 4) outer and 1 or 2 inner, rather long and slender and 

 jointed at the base. The scutum is attached at the middle of the opesia, 

 branched as much as 4 times when fully developed, with as many as 16 

 sharp points, and covers nearly all of the opesia. 



The frontal avicularia are of the "giant" type, somewhat elevated, 

 greatly compressed, the rostrum very elongate with the sides raised to 

 form a groove and without a recurved tip ; the mandible is very long and 

 narrow, extending beyond the rostrum and ending in a broadly curved 

 needle-like point; length of mandible 0.25 to 0.40 mm. The rostrum is 

 directed straight downward between the zooecial series. Usually there 

 is only one frontal avicularium to an internode, but as many as three 

 have been observed. The lateral avicularia are all of the normal tri- 

 angular form, moderately large and present on all of the zooecia. 



The vibracula occur on all of the zooecia; the chamber is small, some- 

 what triangular in outline, the groove nearly transverse ; the seta is short, 

 not much longer than a zooecium; the radicle chamber is on the outer 

 side at the proximal end, the radicle (0.07 mm in diameter) with retrorse 

 hooks. 



Ooecia prominent, subglobose, about 0.20 mm long and wide, with 

 scattered tubular pores. 



This form resembles bertholetti in most of its characters, but when 

 the frontal avicularia are of the extremely elongate type and the scutum 

 is fully developed it appears to be a different species. However, there is 

 so much recorded variation in bertholetti, and some variation in the 

 avicularia and scuta of tenuirostris that it seems better for the present to 

 record the latter as a well-marked variety. 



The writer first observed this form at the Kerckhoff Laboratory at 

 Corona del Mar, California, where it was abundant on the floats and 

 piles of Newport Harbor. Later, in the Hancock collections, it was found 



