The Bryozoa of the Tortugas Islands, Florida. 209 



a smooth, shining appearance or are variously roughened. The secondary 

 layer usually grows irregularly over the primary layer, but in some cases it 

 forms a rather regular raised border with a rounded area of the primary 

 layer exposed on the top. 



This form resembles closely the variety protecta Thornely, as figured by 

 Waters (1909, pi. 17, fig. 5), but the large avicularia are evenly rounded at 

 the tip instead of being divided into points. The peristome also varies 

 greatly. In some cases it is scarcely raised ; in others it takes the form of a 

 tall, broad, median projection, often forked at the tip and projecting so far 

 over the orifice as to nearly obscure it from above. All sorts of intermediate 

 conditions are observed. The peristome also occasionally shows raised 

 lappet-like projections at the side of the orifice, as seen commonly in speci- 

 mens from Massachusetts (Osburn, 1912, pi. xxvii, fig. 65a, 66). In spite 

 of all these variations in secondary characters there is a remarkable con- 

 stancy in the primary orifice, denticle, oral spines, and the primary zooecial 

 walls. 



Another variation, and one which I am at a loss to explain, is this: 

 Some colonies consist of zooecia, the secondary characters of which are all 

 of one type or with little variation, while other colonies will show not only 

 zooecia representing two or more of the so-called varieties, but all sorts of 

 intergradations as well. 



Genus Lepralia (part) Johnston, 1847. 



Lepralia audouinii (d'Orbigny). 



D'Orbigny, 1850-2, p. 401 {Cellepora audouinii). — Smitt, 1873, p. 56 {Escharella 

 audouinii). 



This species, which is known from the Red and Mediterranean Seas, 

 occurs at the Tortugas from low water to 10 fathoms. Colonies taken from 

 the bottom of a skiff which had been in the water from May i to June 23 

 were an inch in diameter, with ooecia containing embryos. In life the 

 colonies are translucent white, but the ooecia often appear light pink when 

 embryos are present. 



Smitt's record was based on a single colony growing on a nullipore at 37 

 fathoms, west of Tortugas. 



Lepralia porcellana Busk. 



Busk, i860, p. 283, pi. 31, fig. 3. — Smitt, 1873, p. 62 {Lepralia deidostoma). — Norman, 

 1909. P- 305. synonymy. 



Taken at 5 to 15 fathoms on shells and on other bryozoa, such as Steg- 

 anoporella magnilabris and Holoporella turrita. The key-hole form of the 

 orifice, the pointed avicularia with elongate mandibles, and the absence of 

 pores except occasional ones at the margin serve to distinguish the species 

 readily. Ooecia present. In one case there is a vicarious avicularium, some- 

 what larger than the usual type, mounted on a smooth, swollen chamber. 

 A low, smooth, umbonate process is sometimes present below the orifice. 



Recorded by Smitt from Pourtales's collections from 30 to 120 fathoms. 



15 



