320 BIOLOGICAL SURVEY OF 



tioiis and thirteen dredging stations. It appears to be at its 

 optimum in this region ; at least the colonies are larger than 

 we have seen them either to the north or south along the 

 American coast. It ranges from southern New England and 

 the Madeira Islands northward to the Arctic Ocean. 



Encrusting shells and pebbles. Sometimes the zoarium may 

 cover 2 or 3 square inches. The zooecia are small, sub- 

 cylindrical, and perforated more or less irregularly by a vari- 

 able number of large, irregular openings. In reality, the 

 frontal shield is formed by the fusion of marginal spines 

 which grow together in an irregular way over the area. The 

 orifice is somewhat semicircular. The loAver border bears a 

 small mucro at the middle which is often bifid (formed by the 

 junction of the anterior pair of frontal spines). Four small 

 marginal spines usually present about the aperture; in the 

 fertile cells the anterior pair is usually fused with the ovicell. 

 Two avicularia are frequently present, one on either side of 

 the orifice, pointing obliquely forward and outward. The 

 ooecium is somewhat elongated, smooth and glossy, and per- 

 forated by a number of small pores. In older colonies the 

 secondary calcification often changes the appearance greatly. 



Cribrilina annulata (Fabricius), 1870. PI. 8, fig. 7. (Os- 

 burn, 1912, p. 232, for synonymy and references; 1912a, p. 

 279, off Cape Sable; WhiteaVes", 1901, p. 98, for Canadian 

 records.) Not common, but occasionally taken on hard bottom 

 and rarely along shore, at three shore stations and six dredg- 

 ing stations. A widely ranging northern species, circumpolar 

 and extending southward along both the Atlantic and Pacific 

 coasts. Cape Cod is apparently near its southern limit on 

 the New England coast. 



Usually in the form of small rounded colonies of a reddish 

 or bro^v^lish color. The zooecial punctures are arranged 

 in definite rows, transverse distally, but tending to radiate 

 toward the proximal end. The primary aperture is nearly 

 semicircular, sometimes with a small denticle on the lower 

 border, but in later stages of calcification this border becomes 

 greatly thickened, especially in the fertile zooecia. Usually 



