PLATE CXXII. 



Fig. 



1. Glandular organs of Filograna implexa, Berkeley, from St. Andrews (1863). Unfor- 



tunately the explanation has been lost. X 180. 



2. Tip of branchia of Pomatocerus triqueter, L. (spirit-preparation), x 40. 



2 a. Operculum of the foregoing, from Lochmaddy, North Uist. Enlarged. 



3. Operculum of Placostegus tridentatus, J. C. Fabricius. X 40. 



3 &. Tip of a branchia (in spirit). X 60. 



4. Operculum of Placostegus, AB., from Shetland, x 40. 



4 a. Outline of tip of branchia in spirit. X 60. 



5. Lateral view of Ditrypa arieMna, O. F. Midler, dredged off North Unst, Shetland. 



Enlarged. 



6. Tip of a branchia (spirit). Enlarged. 

 6 a. Tube. Enlarged. 



6 b. Tube with Garyophyllia attached, from St. Magnus Bay, Shetland,. 



7. Operculum and branchiae of a very young example of Spiroflns granulatus, L., from 



St. Andrews, a, non-ciliated terminal process; b, pinnse; c, opercular disc; 

 e, central calcareous process (talon). X 200. 



7 a. Tube and annelid in life, 1863, St. Andrews. Enlarged. 



7 b. Branchial pinna and peritoneal contents of body of an adult in life. X 280. 

 7 c. Anterior region of an adult showing the anterior granular glands, a. X 40. 

 7 d. Ovum. X 280. 



7 e. Group of ova from calcareous tube. Enlarged. 

 7 f. Embryo in capsule. X 80. 

 7 g. Free embryos. X 80. 

 7h. Eye-specks. X 280. 

 7 i. Operculum. X 40. 

 _JL.Operculum of Spirorbis, CD., Cliff, Scalloway. X 40. 

 9. Operculum of Syirorbis spirillum, L., from Guernsey. X 40. 

 9 a. Operculum of the same from Aberdeen. X 40. 

 _JL&- Tip of branchia (spirit). X 60. 

 10. Operculum of Spirorbis borealis, Daudin. X 40. 

 10 a. Tip of branchia. X 60. 

 ""11^11 a, 11 b. Portions of three massive tubes composed of firm mud and with varying 

 admixture of stones — resembling those of Pista cristata — from the " Porcupine " 

 Expedition of 1869, the first, No. 25, at 164 fathoms, the second off the Hebrides, 

 and the third off Valentia. 

 12. Operculum of Spirorbis militaris, Claparede. Enlarged. 



