The Bryozoa of the Tortugas Islands, Florida. 217 



avicularium with an elliptical mandible, black in color. Sometimes the 

 rostrum is so slightly developed that the avicularium appears to be placed 

 transversely behind the orifice. The operculum is heavily pigmented with 

 dark brown, especially at the edge. Large, spatulate avicularia with 

 brown or blackish mandibles are abundantly distributed over the colony. 

 There is a slight amount of the brownish pigment in the zooecial wall. 

 In all the avicularia the pigment is confined to the mandible, which is thus 

 strikingly contrasted with the colorless basal membrane. In the operculum 

 also the color is limited strictly to the hinged portion and does not extend 

 upon the base. The ooecia are, as in other species of this genus, shallow and 

 widely open, and they are deeply immersed in the crust, except in the very 

 young stage. 



In addition to the specimens mentioned above, a large flat specimen, 2 

 inches across and many layers in thickness, which was apparently growing 

 unattached, was taken by Dr. Paul Bartsch off Biscayne Key, Florida. 

 It has not been possible to identify these specimens with any known species. 

 The large size of the zooecia and the orifice, the great thickness of the walls, 

 even in young specimens, the straight proximal border of the orifice, the 

 absence of a tall rostrum, and the large size of the oral avicularium, together 

 with the elongate form of the mandible with its round tip in the vicarious 

 avicularia, form a set of characters which serve to distinguish it. 



Holoporella turrita (Smitt). 



Smitt, 1873, p. 65 {Lepralia turrita).— Waters, 1883, p. 438 (Smittia turrita); 1909 

 p. 161 (includes in Holoporella, new genus). — Ridley, 1881, p. 55 {Cellepora 

 turrita). — Jelly, 1889, p, 253 {Smittia turrita). 



A very common species at 12 to 15 fathoms, growing on shells, corals, 

 and the firmer sponges. Recorded by Smitt from Pourtales's collections 

 as not frequent, only a few specimens taken, at from 26 to 44 fathoms, 

 growing on corals and nullipores. 



Color in life bright pink to brick-red. Above the spreading incrustations 

 rise knob-like projections, usually 0.25 inch or so in diameter, sometimes 

 much larger. The younger zooecia are separated by delicate, raised, white 

 walls which are very conspicuous against the red color of the colony. The 

 white points of the blunt spines are also strongly contrasted with the ground 

 color. 



Genus Petralia MacGillivray, 1869. 

 Petralia bisinuata (Smitt). 



Smitt, 1873, P- 59 (Escharella bisinuata). — Levinsen, 1909, pp. 350-51. 



This well-marked species, which has not been noted outside of the 

 Florida region, is common at the Tortugas on shells and sponges, from 10 to 

 18 fathoms. The color in life is bright vermilion. Smitt described the 

 species from Pourtales's collections at 9 and 19 fathoms. 



Levinsen (see above) has placed this species in MacGillivray's genus 

 Petralia and has erected a new family, Petraliidae, to include this genus. 



