SCRUPOCELLAEIA HEPTANS. 53 



base of many of the cells a large pedunculate avicula- 

 rium, with the mandible directed downwards. Vibracular 

 cell somewhat curved, with a constriction about the 

 middle, Ooecia subglobose, smooth, with a number 

 of large punctures. Radical fibres either simple, and 

 giving off at the extremity a number of anastomosing 

 fibrils forming a netted disk, or toothed. 

 Polypide with 14-16 tentacles of a light orange colour. 



Habitat. On Algse, Flmtra foliacea, rocks, &c., from 

 between tide-marks to deep water. 



Localities. Universally distributed. It may be found 

 on the most barren coasts. It is more especially a littoral 

 form, spreading luxuriantly over various kinds of sea- 

 weed ; but Mr. Peach records its occurrence on coral 

 taken in 100 fms., from the Outer Haaf, Unst. 



Geographical Distribution. Bahusia and Middle 

 Norway, pretty common in the littoral region (Smitt) : 

 Heligoland (Kirchenpauer) : Red Sea (?) (Savigny): Adri- 

 atic, common on Algae, zoophytes, Polyzoa, &c. (Heller) : 

 north coast of France ; coast of Spain (Kirchenpauer) . 



Range in Time. Scotch Glacial deposits (Geikie). 



Mr. Busk has placed this well-known form in the genus 

 Cauda, Lamx., on the ground that it is destitute of the 

 lateral avicularia, which constitute so striking and distinc- 

 tive a feature of the allied genus Scruj)Ocellaria, Van Ben. 

 Smitt ranks it under his Cellularia, which embraces the 

 last-named group, but agrees with Busk in denying the 

 existence of lateral avicularia"^. In fact, however, the 

 present species is furnished with these appendages, though 

 they are minute and are not developed on all the cells ; 

 and it therefore takes its place of right in the genus 

 Scrupo cellar ia, with which, in all other respects, it entirely 



* "Avicularia latcralia externa desunt '" {Smitt). 



