278 University of California Puhlications in Zoology. [Vol.4 



ing, and articulated (fig. 27). Zooncia oblong, quadrangiilar, al- 

 ternate ; margins broad, separating the roAvs of zoa?cia and fre- 

 quently rising on each side of the orifice into a blunt process (fig. 

 28, &/. pro.) or "tuberosity," or continued in a curved line 

 around the anterior or oral extremity of the zooecium. Orifice 

 large, occupying about one-third of the front, and consisting of 

 tAVO parts; the anterior portion closed by the operculum, op., the 

 posterior part, p. or., by a continuation of the membranous ecto- 

 cyst of the zooecium ; the lower two-thirds of the zooecium covered 

 over most of its surface by a double layer : the membranous ecto- 

 cyst and the calcareous lamina or cryptocyst. Avicularia (pi. 18, 

 fig. 30, sp. av.) large, each occupying the place of a zooecium ; scat- 

 tered irregularly over the surface of a colony, although sometimes 

 lying side by side; mandible triangular, bent or hooked at the 

 tip, directed anteriorly. Ocecia (pi. 17, fig. 29, oe), large, globose, 

 wider than long, often extending half way over the adjacent 

 zooecia; smooth, carinate. not abundant, but occurring in groups 

 irregularly over the colony ; ooecial zooecia of diminished size. 



The habit of growth of this species is characteristic. It is 

 sometimes obtained in its inerusting state only, but usually it 

 combines with this the branching habit of growth. The branches 

 are divided into internodes by joints consisting as in Cellaria of 

 undeveloped zoopcia in whose walls no calcareous deposit is laid 

 down. The outlines of the zooecia, however, are plainly discerni- 

 ble in them. These branching tufts are sometimes large, one 

 being found on the beach at San Pedro, California, consisting of 

 a roll of intertwining branches twenty centimeters long and seven 

 and a half centimeters in its greatest diameter. 



Hincks ('80a) distinguishes three so-called "forms" of T. 

 rozieri, depending upon the possession or non-possession of avi- 

 cularia, ooecia, and tuberosities. He remarks that there is doubt 

 that these differences are of specific value, and any one who has 

 had the opportunity to examine a large quantity of material must 

 not only concur with this opinion, but doubt also their "form" 

 value. According to Hincks, the normal type of T. rozieri pos- 

 sesses ooecia and tuberosities, but no avicularia ; the ' ' form ' ' indica 

 possesses avicularia and ooecia, but no tuberosities; the "form" 

 gothica possesses avicularia and tuberosities, but no ooecia. In 

 our collection, the specimens from La Jolla correspond to the 



