MARINE ZOOLOGY 



3. Sagartia viduata (O. F. Mailer). 



This is common in the Crouch at Burn- 

 ham on the south shore, but seen only when 

 the tide is low. It can be killed in an ex- 

 panded state by using menthol. 



4. Sagartia troglodytes. 



What are probably young or somewhat 

 small individuals of this species are common 

 in the Orwell, a short distance outside Essex. 



5. Ttalia crassicornis (O. F. Mtlllcr). 



I have occasionally caught this in the 

 Crouch when trawling, and it is often dredged 

 in the more open sea. I have collected a fair 

 number of specimens at low water on both 

 the east and west shores of the Colne near 

 Brightlingsea. In 1901 it was very abundant 

 on the shore off Harwich, near the level of 

 extreme low water. 



6. Halcampa chrysanthellum (Gosse). 



Found in sandy gravel near the mouth of 

 the Colne, but the colour of the disk differs 

 somewhat from the Cornish specimens de- 

 scribed by Gosse. 



Though Actinia mesembryanthemum is so 

 common on the coast of Kent, I have never 

 seen one in Essex. 



IV. NEMERTINEA 



1. Lineui obscurus, Desor. 



The only place where I have found this is 

 in the mud at Mistley. 



2. Amphiporus lactifloreus, Johnston. 



I have found only one specimen, which was 

 obtained in the Orwell a short distance out- 

 side Essex. 



V. NEMATODA (?) 



Nectontma (?) 



I have never seen more than one specimen, 

 which was caught wriggling about at the sur- 

 face in the Stour off Harwich. It is 11$ 

 inches long and ^ inch thick and full of eggs, 

 and is almost certainly a fish parasite which 

 had escaped from its host when mature. 



VI. ANNELIDA 

 I. POLYCH^ETA 



I. Aphrodita aculeata (Linn.). 



This used to be fairly common in the Stour 

 off Harwich, but lately I have not obtained 

 it there. It is much more common in the 

 Wallet near the Gunfleet bank. 



2. Lepidonotus squamatus, Linn. 



This occurs commonly in most parts of the 

 district. It is often found in the tubes of 

 Amphitrite Johnstons. 



3. Nereis diver sicoler, Mull. 



Very abundant in the mud banks of St. 

 Osyth's creek and found in most other Essex 

 estuaries, though comparatively rare in the 

 Crouch. In some places it is much coloured 

 by a fugitive green pigment, and in others 

 coloured red by the great amount of hemo- 

 globin which is comparatively absent in others. 

 In some places almost at high water mark and 

 up the estuaries far from the sea it is abundant 

 to the exclusion of other similar animals. 



4. Nereis cultrifera (Grube). 



Common in particular places in sandy mud 

 near low water mark at the mouth of the 

 Colne and off Harwich. 



5. Nereis pt/agica, Linn. 



All the specimens I have procured were 

 dredged outside Harwich harbour, where it 

 occurred amongst the sandy tubes built by 

 Sabellaria spinulosa. 



6. Nereis dumerilii y Aud. & M. Edw. 

 Readily distinguished from the three other 



species by having very long tentacular cirri. 

 I have always found it in tubes built amongst 

 alga. When kept in a small aquarium it 

 built a semi-transparent tube open at both 

 ends and came out and ate Ulva and returned 

 to its tube. It laid very many eggs without 

 passing into the Hettranereis condition. What 

 I believe was the same species passed into that 

 condition in my larger aquarium, but they 

 may have been males. Though I have lived 

 in the Orwell and Stour for a total period of 

 between one and two years I seldom if ever 

 saw Heteronereis except in the early morning 

 of July 1 6, 1898, when males of about 2 

 inches long were swimming on the sur- 

 face in Harwich harbour in such numbers 

 that I estimated them at something like a 

 million. When dried and mounted in Canada 

 balsam this species differs from all the others 

 in turning deep brown, but this does not hap- 

 pen in the case of the male Heteronereis. 



7. Nephthys hambergii (Cuvier). 



Common in the more or less sandy mud 

 exposed at low water in the Colne and near 

 Harwich but much rarer near Burnham. 

 It varies considerably in colour owing to the 

 greater or less amount of hzmoglobin and of 

 a brown pigment. 



79 



