3908] Rohertson. — Incrusting Bryozoa. 293 



surface; number vniyiufi' between three and five depending on 

 the size and shape of the zocccia. 



The possession of adherent calcareous tubes allies this species 

 to SchizoporeUa argcntea Hincks ('85). Of this species Hincks 

 writes, "set round the edge are six prominent tubular projections 

 with which probably some chitinous appendage may be connected. 

 On the sutures between the cells (zocecia) are six rather large for- 

 amina which pierce through the zoarium and open out on the 

 front surface, so that the zoa?cia may be regarded as to some ex- 

 tent, disjunct, and attached to one another by six broad connect- 

 ing processes (pi. 9, fig. 6a)." In S. oligopus there is no indica- 

 tion of a chitinous appendage to the tube feet. However, the 

 portions of the colony from which this description is written were 

 not obtained in situ, so that the sort of substratum upon which 

 it grew as Avell as the sort of adherence is unknown. Each tub- 

 ular prolongation is lined by a continuation of the epithelium 

 lining the zooecium, and in some cases this epithelium is pulled out 

 into a 'long process (fig. 50, ep. pro.) beyond the tube foot, sup- 

 posedly by the force separating it from the substratum. At the 

 angles formed by the union of three zooecia, foramina (fig. 51, 

 for.) are sometimes found piercing the zoarium, but these are not 

 as numerous nor as constant as are those of S. argentea. 



It is a question whether or not the peculiar method of ad- 

 herence characteristic of these two species S. oligopus and S. ar- 

 gentea may be sufficient to remove them from the present genus. 

 However, it is not considered advisable to do so, until more ma- 

 terial is obtained and until the zoarium is found in situ and its 

 growth habit carefully studied. 



Schizoporella oligopus was dredged in the vicinity of San 

 Pedro, California. 



63. Schizoporella tumulosa Hincks. 

 PI. 20, fig. 53. 

 Schi-oporella tvmulo.m Hincks, 1883, vol. 11, p. 447, pi. 18, fig. 2. 



Zoarium forming a thick, white, calcareous crust over shells. 

 Often growing several layers thick, one on top of the other, the 

 calcareous deposit becoming thicker with each layer. Zooecia 



