BRYOZOA OF WOODS HOLE REGION. 239 



fertile cell, the position of the avicularium which is at the base of the rostrum and is directed laterally 

 and but slightly upward, in the much greater development of the rostrum above the avicularium, in 

 the absence of the small lateral avicularia and the large pointed avicularia described by Hincks for 

 avicularis. It may possibly prove to be only a variety of avicularis, but after careful comparison with 

 specimens of that species from England, I believe it to be sufficiently different to rank as a separate 

 species. 



Abundant in Vineyard Sound, not common but well distributed in Buzzards Bay, dredged in 

 i to 19 fathoms; also in drift on the shores of No Mans Land and Nantucket, and near Sandwich on 

 the north shore of Cape Cod. 



Cellepora canaliculata Busk. [PI. xxv, fig. 53, 533, 53b, pi. xxxi, fig. 98.] 



Busk 1884, p. 204. 



Verrill 18790, p. 30 (C. tuberosa). 



Whiteaves 1901, p. 109. 



Zoarium encrusting on stems of hydroids and Bryozoa, usually in rounded "pisiform" colonies, 

 but I have one fine specimen taken at Crab Ledge which has an irregular branching structure. Zooecia 

 somewhat ovate in young colonies, punctured around the base, smooth, in older colonies the cells erect, 

 or nearly so, and very irregularly disposed, orifice rounded with a rather broad sinus; back of the orifice 

 rises a stout, elongate, curved rostrum, bending somewhat over the orifice and bearing at its tip a small 

 round avicularium; from the sides of the thin peristome a broad flange rises to the sides of the rostrum, 

 producing a broad spout at the bottom of which the primary aperture is situated. Ovicell rather large, 

 broader than high, flattened above near the orifice, irregularly punctured. 



Taken only at Crab Ledge in 15 to 20 fathoms, where it seems to be well developed but not common. 

 The type locality of the species was near Halifax, Nova Scotia, in 51 fathoms (Challenger); and the 

 species has subsequently been taken in the Gulf of St. Lawrence. 



Family ESCHARID^ Smitt (pars), 1867. 



This rather heterogeneous family is distinguished among the others of our region rather by the 

 absence of certain characters than by the presence of well-marked structures constant for the group. 

 In the form of the primary zooecial orifice the different genera exhibit a wide range. From the families 

 with a semicircular orifice fCribrilinidse and Microporellidse) the absence of a special pore and the 

 formation of the zooecial wall are sufficiently distinctive, while from the Myriozoidae the absence of a 

 distinct sinus in the posterior margin of the primary orifice is characteristic, though it may require careful 

 scrutiny of the younger zooecia to determine this, since a sinus may appear secondarily in the peristome. 

 In general, the family is characterized by the great development of secondary characters, and the 

 appendages are extremely varied. 



KEY TO GENERA. 



1. Primary orifice without posterior tooth or shelf, no suboral avicularium, spine or mucro, secondary 



orifice, when raised, never sinus-like at the posterior margin Lepralia. 



One or more such characters present 



2. Posterior margin of orifice more or less developed into an overhanging prominence or mucro which 



never bears an avicularium Mucronella. 



Posterior margin of orifice not mucronate, or, if so, the mucro bears an avicularium on the side or 

 at the tip 



3. A prominent suboral mucro (usually placed a little to one side of the median line) bearing an avicu- 



larium on its side, sometimes a similar projection (without an avicularium) on the opposite of the 



midline; orifice very large; zooecial wall delicate and shining . .Rhamphostomella. 



Characters otherwise 4- 



