-'^^^^ lioheiison.—Incrusting Bryozoa. 



287 



front wall pnnetiiivd. Orifice small, rounded above with a def- 

 inite sinus on the lower margin. Some distance below the sinus, 

 an oval or slightly elongated avicularium (pi. 19, fig. 40, av.), 

 immersed, or if raised, only very slightly, mandible directed 

 straight downward. Ocecia subglobose, small, immersed, punc- 

 tured. 



This sub-species was obtained in small quantity near San 

 Pedro, dredged in 32.5 fathoms. 



56. Schizoporella biaperta (JMichelin) Hincks. 



PI. 19, fig. 41. 



Eschara biaperta Michelin, 1841-42, p. 330, pi. 79, fig. 3. 



Eeptoporina biaperta, d'Orbigny, 1850-52, p. 442. 



Lepralia biaperta, Busk, 1859, p. 47, pi. 7, fig. 5. 



Escharella linearis, forma biaperta Smitt, 1867, pp. 14 and 98 pi 



24, figs. 70^ 73. " ' ' 



Hippothoa biaperta, Smitt, 1873, pt. 2, p. 46, pi. 8, figs. 173-176. 

 Eippothoa divergens Smitt, 1873, pt. 2, p. 47, pi. 9, figs. 177-179. 

 Lepralia linearis var. biaperta, Waters, 1879, vol. 3, p. 37 pi 11 



figs. 1, 2. ' • ' 



Schizoporella biaperta, Hincks, 1880, p. 255, pi. 40, figs. 7-9. 

 Schizoporella biaperta, Eobertson, 1900, p. 326. 



Zoarium forming an irregular crust over the substratum of 

 shells, stems, etc. Zomcia ovate, slightly convex, surface hyaline, 

 punctured in the younger stages, becoming thicker and granular 

 in the older stage, always marked by faint anastomosing lines 

 (pi. 19, fig. 41). Orifice circular, M'ith a distinct sinus whose 

 lateral walls are slightly raised ; peristome low. On each side of 

 the orifice an elevated avicularium with small triangular mand- 

 ible directed upward ; occasionally on the lower part of the zooecia 

 a larger avicularium, av., elevated upon a rounded prominence. 

 Ocecia, oe., rounded, the front Avail flattened and traversed by 

 radiating lines. 



The zoa'cia bearing the ovicells are not invariably of a differ- 

 ent size and appearance from those that do not possess these 

 structures as Hincks ( '80) seems to imply. The smaller zooecia 

 and the mamillated avicularia occur generally in the more 



