246 BULLETIN OF THE BUREAU OF FISHERIES. 



shining, perforated by numerous rounded pores, becoming rougher with age; orifice rounded, with a 

 small posterior tooth which is pointed or bifid or occasionally entirely wanting; immediately behind 

 the orifice is an oval avicularium with the rounded mandible turned upward; peristome thin, more or 

 less raised, when fully developed partly surrounding the avicularium. Ooecia subglobose, prominent, 

 punctured. 



The oral avicularium is sometimes wanting, and I have not noted spatulate avicularia on our 

 specimens. 



Occasionally taken at Crab Ledge in 14 to 20 fathoms, and at Great Round Shoal in 8 fathoms. 



Smittia trispinosa (Johnston). [PI. xxvn, fig. 65, 6$a.] 



Johnston iSjS, p. 280 (Lepralia trispinosa). 

 Davvson 1859, p. 256 (Lepralia trispinosa). 

 Packard 186.3 and 1869, p. 67 (Lepralia trispinosa). 

 Verrill iSygb, p. 195, and 18790, p. 31 (Afucrondlajacotini). 

 Whiteavcs 1901, p. 106. 



Zoarium encrusting on stones, shells, etc., forming whitish to yellowish colonies which are at first 

 thin and smooth, but later rough and much thickened. Zooecia more or less ovate to quadrangular, 

 in young colonies disposed with more or less regularity, but in older colonies extremely irregular, sepa- 

 rated by a raised border; surface smooth and shining to more or less granular, with a row of areolae around 

 the border, these areolae separated by strong, but short, ribs in older specimens; orifice rounded in front, 

 nearly straight behind, with a squared tooth projecting from the posterior border; peristome usually 

 but little raised in our specimens, though occasionally there is a lamina on either side of the orifice 

 projecting upward; two to four oral spines usually present in young cells. Two kinds of avicularia 

 are present, one with a pointed mandible, the other with the mandible rounded to spatulate; the first 

 of these is large and is usually placed at one side of the orifice with the mandible directed forward and 

 inward, but it may be situated anywhere on the cell with the mandible turned in any direction; the 

 oval avicularia are usually small and situated on the basal part of the cell, but they may take the place 

 of the pointed kind at the side of the orifice; moreover, they vary in length of the mandible, and, while 

 they are usually oval, they are not infrequently elongate or spatulate in form. Ooecia large, globose, a 

 little flattened above, smooth or somewhat roughened, with a few large irregular punctures. 



The greatest possible variation exists in the occurrence and disposition of the avicularia; some- 

 times only the pointed ones are present, again only the oval ones, but both kinds are frequently present 

 and several of them on a single cell, or the oval ones may be more or less spatulate, and not infrequently 

 they are all absent. 



Not uncommon at Crab Ledge in 14 to 20 fathoms. Taken also in Buzzards Bay near Penikese 

 Island (Fish Hawk station 7672). The species is widely distributed on both sides of the Atlantic. 



Smittia trispinosa var. nitida (Verrill). [PI. xxvii, fig. 66, 66a, 66b, 66c, 66d, 66e, pi. xxx, fig. 88.] 



Verrill 18753, p. 415 (Discopora nitida n. s. p.) 1879!}, p. 195, and 18790, p. 30 (Mucronella nitida). 



Encrusting on anything which affords a basis for attachment, most common on stones and shells; 

 at first forming glistening, white colonies of regular appearance, later piling up in masses, and often 

 completely surrounding pebbles and small shells in yellowish nodular masses of considerable size, 

 occasionally rising into low frills on the stems of algae and in similar situations. The general form and 

 character of the zooecium is that of trispinosa, but the cells average smaller, and the aperture is corre- 

 spondingly smaller than in the typical form. The variations in calcification are about as in trispinosa. 

 The peristome is usually raised, sometimes evenly, but generally in older stages it is irregular; the 

 most common form is with a labiate process rising on either side of the orifice. Avicularia are abun- 

 dantly developed, of two sorts, a small oval (occasionally somewhat pointed) type situated usually on 

 one or both sides of the orifice, and a larger, oval or often spatulate, form irregularly located on the front 

 of the cell behind the aperture. (This form of avicularium was not mentioned by Yerrill, but is of 

 frequent occurrence.) An umbonal process is sometimes placed irregularly behind the orifice. Oecia 



