302 University of California Publications in Zoology. [Vol.4 



Zoarium iiicrnstino:. Zooecia with the primary orifice siibor- 

 bieiilar, the lower margin entire and dentate; peristome elevated 

 and forming a secondary orifice which is channelled in front; 

 generally an avicidarium below the secondary sinus. 



KEY TO SPECIES OF SMITTIA. 



1. Frout wall porous over the whole surface 2 



1. Front wall with marginal pores very marked, frontal pores, if 



present, few and indistinct 4 



2. Avicularia median S. landsborovi 



2 Avicularia not median :. 3 



3. Avicularia on one or both sides of orifice, sessile S. trispinosa 



3. Avicularia on one or both sides of orifice, raised on a high mound 



S. calif omiensis 



4. Frout wall with prominent processes S. collifera 



4. Front wall without blunt processes 5 



5. Front wall granular, marginal pores large and separated by dis- 



tinct ribs - S. reticulata 



71. Smittia trispinosa (Johnston) Hincks. 



PI. 22, figs. 68, 69, 70. 



Lepralia tyispinosa Johnston, 1847, ed. 2, p. 324, pi. 57, fig. 7. 

 Lepralia variolosa Johnston, 1847, ed. 2, p. 317, pi. 55, fig. 8. 

 Lepralia trispinosa, Busk, 1854, pt. 2, p. 70, pi. 25, figs. 1, 2 ; 



pi. 98. pi. 102, fig. 2. 

 Lepralia trispinosa, Hincks, 1877, vol. 19, p. 100, pi. 11, fig. 1. 

 Escharella Jacotini, Smitt, 1873, p. 59, pi. 10, figs. 199, 200. 

 Smittia trisijinosa, Hincks, 1880, p. 353, pi. 49, figs. 1-8. 



Zoarium forming a rather thick, spiny whitish incrustation on 

 shells, stems of seaweed, etc. (pi. 22, fig. 70). Zooecia elongate- 

 ovate, sometimes quadra ngnlar, in linear series, alternate; front 

 wall convex, granular, punctured round the edge with large 

 pores ; similar pores frequently scattered over the surface, though 

 sometimes lacking; primary orifice (fig. 68, pr. or.) circular or 

 suborbicular ; secondary orifice (fig. 69, sec. or.) formed by a 

 high, thin peristome possessing a deep sinus, s., within which a 

 denticle, d., is usually visible. In young stages two or three 

 spines (fig. 68, sp.) on the upper margin of orifice; spines fre- 

 quently developed on every zooecium of the colony. Avicularia 

 usually very abundant and very variable in shape and loca- 

 tion. Generally one of large size on one side of the orifice, some- 



