234 BULLETIN OF THE BUREAU OF FISHERIES. 



Zoarium encrusting, on stones or shells, occasionally on algae, forming silvery or white rounded 

 colonies, often an inch or more in diameter, but usually smaller. Zooecia ovate, or when more crowded, 

 rather elongate hexagonal; when young, thin-walled and silvery and punctured with numerous small 

 pores, when older, and especially in deep water, the calcification proceeds much farther and the walls 

 become much thickened, rough, often flat on the surface or occasionally very gibbous, and the punctures 

 are obscured. Orifice semicircular, the border usually but slightly raised, generally with 4 oral spines 

 curved outward; immediately posterior to the orifice is a special median pore which is usually more 

 or less lunate in form, and with teeth or spinules projecting into it; an unbonate process often occurs 

 just behind the pore, partly or entirely obscuring it from above. Ovicell rounded or slightly elongate, 

 frequently punctured, often sculptured with radiating ridges, and occasionally with an umbonate 

 process at the top. Avicularia, usually one (occasionally two), situated on the side a little way behind 

 the orifice, with a more or less sharply pointed mandible directed, usually, forward and outward. 



The species is extremely variable. Depending on the amount and the manner of calcification the 

 zooecium may be thick or thin walled, rough or smooth, flat or gibbous, punctured or entire, umbonate 

 or not. The avicularia vary from short triangulate to very elongate. The pore varies with the size 

 and shape of a projection on its anterior lip; usually this projection is evenly rounded and broad so 

 that the pore is lunate in form, but very frequently the pore is nearly round, with a spinous stalked 

 knob projecting from the anterior border into the pore. This latter condition leads up to the variety 

 stellata, in which the pore becomes round and the spinous knob is wanting. There are also enormous 

 differences in the size of the zooecia. 



Taken with some frequency in the outer waters of the region. Lower end of Buzzards Bay, both 

 ends of Vineyard Sound, Crab Ledge, Great Round Shoal, and Nantucket Shoals. Dredged in 7 to 

 20 fathoms. 



Microporella ciliata var. stellata (Verrill). [PI. xxiv, fig. 45.] 



Verrill iS/sb, p. 53; i87gb, p. 190, and 18790, p. 29 (Porcllina stellata). 



"A large species forming radiate patches on shells, etc. Zooecia arranged in quincunx, large, 

 broad, moderately convex, white shining, mostly imperforate and smooth, the marginal ones more or 

 less perforate in front. Apertures nearly semicircular, the proximal edge straight or nearly so, often 

 with two spines on the distal border; median pore a short distance from the aperture, large, nearly 

 circular, provided with numerous slender, convergent spinules, which nearly reach the center, giving 

 the pore a stellate appearance. Avicularia near the lateral margin, about opposite the median pore, 

 varying in size and form; in the same colony some are short triangular, while others with a long and 

 acute, erect tip show the transition toward vibracula. The zooecia are about twice as large as those of 

 ciliata. Casco Bay, Me., U. S. F. C., 1873." (Verrill.) 



As every character on which the above description is based is subject to great variation, I can not 

 consider that stellata is entitled to rank as a separate species, particularly as a study of a large number 

 of specimens from the North American coast shows so many intergradations. The nearly circular, 

 stellate character of the pore, caused by the absence of any projection on the anterior side, is the only 

 character of any differential importance, and, as I have shown in discussing ciliata, this condition is 

 merely the end of a series. 



This form occurs with the normal ciliata in the eastern end of Vineyard Sound, Muskeget Channel, 

 Great Round Shoal, Crab Ledge, and Nantucket Shoals. 



Family MYRIOZOID Smitt (pars), 1867. 



Authors have been at great variance in their use of this family. Smitt (1867) included certain 

 species now placed in the genus Smittia of the family Escharidse, in which family he included the genus 

 Cellepora, but later (1872) he included this genus within the limits of this family. Hincks (1880) sepa- 

 rated Cellepora widely from the Myriozoidae, following Johnston and Busk in making it the type genus 

 of the family Celleporidae. On the other hand Jullien and Calvet (1903) have separated the family 



