236 BULLETIN OF THE BUREAU OF FISHERIES. 



colonies often separated by areolated spaces; surface hyaline, glossy, and transversely grooved; orifice 

 rounded, with a broad, well-defined sinus in the posterior margin, but this is often obscured from above 

 by an overhanging umbonate process. Goecia globose, puncttu'ed, borne on slightly dwarfed zooecia 

 which stand nearly erect among the other cells. No avicularia. The variations are mostly due to the 

 character of the substratum and to crowding. 



An abundant species, occurring from low water to 20 fathoms, and distributed throughout the region. 

 Buzzards Bay, Vineyard Sound, No Mans Land, Nantucket, Crab Ledge, and Great Round Shoal. At 

 the last place it was extraordinarily abundant, encrusting the stems of hydroids. It is a cosmopolitan 

 species. 



Genus SCHIZOPORELLA Hincks, 1880. 



This genus presents a great range of variability, embracing practically all the characters. Perhaps 

 the most constant feature is that which suggested the name, the presence of a distinct notch or sinus 

 in the posterior border of the primary zooecial aperture. In many cases this is obscured in older zooecia 

 by secondary calcification, but the examination of the yoimger cells of the colony will show the character. 

 The absence of denticles projecting from the lateral or posterior border into the orifice is also useful in 

 separating the genus from certain of the Escharidfe. 



KEY TO SPECIES. 



1. Avicularia usually present, surface punctured, ovicell without special pore at the summit 2. 



Avicularia absent, the ovicell with a special pore, primary orifice usually obscured sinjwsa. 



2. Avicularia pointed, usually placed on one or both sides of the lower border of the aperture with 



the mandible pointing forward and outward, occasionally reversed or otherwise placed .unicornis. 

 Avicularia rounded or spatulate, not pointed 3. 



3 . A small oval avicularium on a raised projection at either side of the orifice (often on only one si'de\ 



ovicell with a depressed area traversed by radiating furrows biaperta. 



A small rounded avicularium situated centrally immediately below the sinus (occasionally wanting); 

 depressed area of ovicell with regularly arranged pores instead of furrows aiiricuhta. 



Schizoporella unicornis (Johnston). [PI. xxv, fig. 48, 48a, 48b, 48c, 48d, 486, pi. xxx, fig. 91.] 



Johnston 1847. p. :!,20 {Lepralia unicornis). 

 Desor 1848, p. 66 (Lepralia variolosa). 

 I.eidy 1855, p. 142 (Esckarina variabilis). 

 Verrill and Smith 1874. p. 713 (Escharella variabilis). 



Verrill iS75b, p. 41 {Hippotlioa variabilis); ibid. p. 41, pi. iii, fig. i (Hippothoa reversa, n. sp.); iS79b. p. 193, and 1879c. p. 30 

 (Esckarina isabelliana D"Orbigny. E. reversa Verrill. and E. ansata Gray). 



Zoarium forming a reddish incrustation, often many layers in thickness, on an^^thing which will 

 afford attachment, most frequently on shells, stones, and worm tubes, though tlie largest colonies I have 

 seen were on the bark of wooden piles; occasionally the colony rises into f ree e xpansions of a very irregular 

 form which are low. The color varies in life from pale orange to a dark brick-red, sometimes colorless 

 and shining in deeper water. Zooecia more or less ovate, hexagonal, or rectangular, often broad and 

 squarish, sometimes rather flat and again very gibbous, the surface sometimes smooth and glossy, but 

 more often rough and tuberculate; punctured with a variable number of small pores which have no 

 apparent order of arrangement, occasionally forming irregular areolse around the margin; an umbo of 

 variable size immediately below the orifice, not infrequently wanting; the cells may be separated by 

 a deep groove, or a raised wall may be present around the border (form ansata); orifice semicircular or 

 subcircular, the posterior border nearly or quite straight, with a rather large rounded sinus, no raised 

 peristome or oral spines. Ovicell subglobose, not immersed, punctured, usually rather smooth near 

 the orifice and more or less grooved in a radiating manner on the sides, often very rough when fully 

 calcified, and not infrequently bearing a rounded umbo at the top. Avicularia one or two, placed 

 laterally just behind the orifice, the mandible, which is usually short triangular, but may be elongated, 



