1908] Robertson. — Incrusting Brijozoa. 307 



76. Phylactella coUaris Norman. 



P]. 23, fig. 77. 



PhylactcUa colhiris Xormaii, 1866, p. 204. 

 Flii/hicteUa collaris, Hincks, 1880, p. 358, pi. 43, fig. 3. 



Zoarium incrusting' small pebbles. Zooecia somewhat irreg- 

 ularly arranged, sometimes alternate, sometimes side by side and 

 again without order ; depressed proximally, raised distally, punc- 

 tate. Orifice (pi. 23, fig. 77, pri. or.) in younger stage, orbicular, 

 with well developed lateral denticles; acquiring a flaring peris- 

 tome which in zocpcia that do not possess an ovicell forms entirely 

 around the primary orifice ; more expanded at the sides and in 

 front ; in ooecial zooecia rising in front of the ovicell on each side 

 and forming a frill-like expansion; peristome sometimes pro- 

 longed downward in the median line into a thickened point, again 

 upturned into a mucro-like projection, pro., which partially hides 

 the large orifice. Ooecia thickly punctured, appearing somewhat 

 depressed behind the high peristome. 



The species here identified as Plujlactella coUaris Norman is 

 evidently related to that species and yet differs from the descrip- 

 tion usually given for the type species. The zooecia of the Cali- 

 fornia specimens are larger than those of the type, and the wall 

 is profusely punctured. According to Hincks ('80), P. collaris 

 is subgranular, and in his original description Norman {'66) 

 describes the zooecia as ' ' granular, not punctured round the mar- 

 gin." A specimen from Plymouth, England, however, dredged 

 at 4 to 25 fathoms, has the front wall distinctly punctured. Evi- 

 dently this character is a variable one, and the peculiar collar- 

 like expansion of the peristome together with the orbicular prim-, 

 ary orifice, in the absence of other distinguishing mark, connects 

 it too closely with the present species to warrant its removal. 



Dredged in 45 fathoms on the west coast of the island of Santa 

 Catalina, off the coast of southern California. 



Mucronella Hincks. 



Berenicia (part) Fleming, 1828. 

 Lcpralia (part) Johnston, 1847. 

 Lepralia (part), Busk, 1854. 

 Discopom Smitt, 1867. 

 MucnnuUd lliucks, 1880. 



