472 SUPPLEMENT. 



Generally upon Ascidia, in fine fruit off Aberdeen June 1846, 

 also in Orkney. Those in Groadby are from Buchanness. 



P. FRUTESCENS from muddy bottom in forty-five fms. off the Tees, 

 in April 1845, and again in March 1846, both times with 

 ovaries. 



LAOMEDEA DICHOTOMA I send some from Firth of Forth, and 

 another species, which closely invests old polypidoms of A. 

 antennina or T. indivisa, from Estuary of Thames. Both 

 species have crenulated margins, the southern more distinctly 

 so. Before the rupture of the operculum the markings of the 

 future crenations have been observed upon the walls of the 

 cells. It is unnecessary to repeat here what I have said in a 

 former letter. 



LAOMEDEA GELATINOSA a with even margins and simple stem 

 (not seen by me,) /3 with crenulated margins, and simple stem, 

 y with margins, and compound stem. The second 



species or variety occurs in thirty -five fms. off Yorkshire coast. 

 Forty fms. Buchanness, and four fms. Kirkwall Bay. The 

 third variety is from thirty-five fms. off Copinsha, but the cells 

 have not been examined. 



LAOMEDEA GENICULATA Orkney Islands, &c., generally upon Lami- 

 naria, but sometimes upon rocks. This species, of all the 

 Laomedea, is the most constant to its character, its circum- 

 flexuose (not angularly bent) stem and short pedicles, with 

 entire margins to the cells distinguish it at once. Is not Van 

 Beneden's C. geniculata L. dichotoma of Firth of Forth ? I 

 have sent sketches of the embryo already. 



CAMPANULARIA VOLUBILIS Estuary of Thames to Orkney Islands. 

 It is usually found upon Laomedea dichotoma. F. of Forth, 

 when the difference in the thickness of the cell-walls is well 

 seen by contrast. 



CAMPANULARIA SYRINGA Thames to Orkney Isds. The operculum 

 is eight-sided. N.B. The operculum of S. tamarisca is formed 

 in the same manner, but is of only three sub-rhomboidal pieces. 



CAMPANULARIA VERTICILLATA in fine fruit, in June, Firth of Forth, 

 1846 very large off Copinsha (nine inches). 



CAMPANULARIA DUMOSA a, erect, irregularly branched cells sub- 

 sessile. /3, erect, distichous branches secundate falcate 

 cells upon once-twisted foot-stalks, four completing a whorl, and 

 so disposed as to form four nearly perpendicular rows upon the 

 branch (specimens sent in 1845). y, creeping-cells sub-sessile. 



