THE DIRECTOR S REPORT. 5 



during the past year shows that a g-i'eat change has taken place 

 within the Sound itself. Plymouth Sound is properly included 

 within a line drawn from Penlee Point to the Mewstone. The 

 breakwater divides it into two great areas, of which that lying 

 within the breakwater is nearly a closed basin. During the months 

 of July and August I explored the whole of this inner region very 

 carefully, and extended my researches southward to the imaginary 

 line which limits Plymouth Sound. Previous to my arrival there 

 the same localities had been constantly dredged by Messrs. Heape 

 and Cunningham, so that one may say that the Sound has been 

 carefully explored throughout a whole year. The result is that we 

 find that very many of the animals which were known to be plentiful 

 in the Sound twenty years ago have migrated further out, and are 

 no longer to be found within the breakwater. This is no doubt 

 due to the great increase of the Three Towns, and to the largely 

 increased outfall of sewage, the whole of which is poured directly 

 into what I have already described as a nearly landlocked basin ; 

 in many places, indeed, the ground is so foul that no animal would 

 have a chance of subsisting there. This is particularly the case 

 northward of the Breakwater Fort, and along the line of buoys 

 to the north of Drake's Island. It is not advisable to attempt to 

 give a complete list of all the species recorded, but attention may bo 

 called to some of the more important forms which occur in the Sound. 



The Protozoa have not been worked out. Of the Porifera, Grantia 

 ciliata and G. compressa are very abundant. Oscarella lohularis is 

 not uncommon, and Clathrina clathnis is abundant in certain caves 

 beneath the Laboratory. The rocks are covered everywhere with 

 Halichondria panicea. Hymeniacidon suherea and Isodictija lohata 

 are also found, the former in abundance, the latter rarely. 



Of the Hydrozoa the most important is Mijriothela phrygia, which 

 is found on the underside of stones to the east of Drake's Island. 

 Tahularki indivisa, common twenty years ago, can rarely be found 

 now. Clava carnea and G. midticornis occur only in small colonies. 

 Eudendrium raviosum, Hydractinia echinata, Ilalecium halecinum, 

 several species of Ohella, Clytia Johnstoni, different species of 

 Sertularia, Sertularella and Plumularia , with Antennularia anten- 

 nina and A. ramosa, nearly complete the list. One hardly ever 

 obtains a fine hydrozoon colony within the Sound, the large specimens 

 come from deeper water and cleaner ground. 



The Anthozoa are well represented in number, though not in 

 variety. The most notable species is Bolocera ecpues, which occurs 

 in the Cattewater. Caryophyllia Sinithii, the common Devonshire 

 coral, is tolerably abundant, and various species of Say art ia, Bunodes, 

 and Tealia occur in the Sound. One of the most common forms is 



