298 BIOLOGICAL SURVEY OF 



the British Museum for comparison. It is quite possible 

 that it has been recorded under other names by former 

 authors. Whiteaves (1901, p. 110) lists it as common in the 

 Gulf of St. Lawrence, but specimens in the British Museum 

 from Canada, in both Hincks' and Norman's collections, 

 belong in part to the new species described below, according 

 to Miss Hastings, who has furnished me with the following 

 notes concerning the species : 



"The holotype from Shetland unfortunately has no ooecia, 

 but there are ovicelled colonies from Shetland in the Norman 

 Collection, which I take it can be regarded as paratypes. They 

 include the one figured by Hincks (1880, Brit. Mar. Pol., pi. 63, 

 fig. 4)." 



The species appears as a simple fan-shaped or lobulated 

 incrustation on stones and shells. The layer is only moder- 

 ately thick, and usually two rows of incomplete zooecia appear 

 distally to the youngest mature ones. The horizontal portion 

 of the tubule is punctured, though in older specimens the 

 punctures may be covered by a secondary layer of calcifica- 

 tion. The average width of the horizontal tubules is about 

 0.32 mm., and the zooecial aperture measures about 0.15 mm. 

 The ooecia resemble the zooecia rather closely, but are slightly 

 more swollen and more thickly punctured. Often several of 

 them appear in one colony. The ooeciostome is about one-half 

 the diameter of the zooecial aperture (about 0.08 mm.), much 

 less prominent than the erect portion of the tubule, and near 

 the distal end of the zooecium, which appears to slope away 

 from it. No doubt the general similarity of the ooecium to 

 the zooecia has prevented its earlier discovery, though they 

 are distinct enough, and Miss Hastings has discovered it on 

 the specimen from Shetland which was figured by Hincks 

 (B. M. P., pi. 63, fig. 4) from a specimen in the Norman Col- 

 lection. Miss Hastings writes, ''Your discovery of the ovi- 

 cells of S. diastoporides finally disposes of Smitt's suggestion 

 (K. svensk. Vet. Akad. Forh., 1871, p. 1117) that Me.^enferi- 

 pora meandrina Wood is the full-grown state of S. diasto- 

 porides." 



