A DAY ON THK CROUCH RIVER. 151 



slug's back. One brilliant specimen of the bright purple Eolis 

 ccronnfa, and another dark reddish-brown species of Eolis (either 

 Eo/is conciitfia, Alder and Hancock, pi. 24, or a new species) 

 occurred, but these slugs are difficult to preserve, even to make 

 subsequent indentification possible. Doris can be kept well, Doto 

 fairly well, though it loses its bright colours, but attempts to preserve 

 Eolis are quite failures. These slugs are handsome and conspicuous 

 objects when separated from their surroundings, but amongst the 

 various living Zoophytes and Algce their protective resemblance is 

 remarkable and they are by no means easily recognised amongst the 

 varied contents of the dredge or trawl. 



Corallines or Zoophytes were, of course, abundant, but we were 

 neither of us specialists enough to recognise many. Hydractinia 

 echinata was common on the shells of Purpura iapillus, living and 

 beautiful ; much interest was shown in two specimens we bottled. 

 The presence of a fine " root " of Tubularia indivisa in a jar, with 

 its rich bouquet of delicate, but brilliant, white-plumed scarlet flowers, 

 was also a great surprise to our crew. This Tubularia occurred 

 many times in the deeper water near the mouth of the river, as did 

 also a brilliant orange species, almost equally beautiful, but whose 

 name we did not know. Sertularians were abundant, but all we 

 recognised with certainty were, Serhilaria pumila, S. alnetiua, S. 

 Jilicula, S. argentea, and Hydrallmannia falcata on S. pumila. 

 Among the Escharids Cellnlaria avicularia and Eschara foliacea 

 appeared to be common. 



Of the sponges, several fine pieces of Chalina oculata were 

 noticed, and both Grantia ciliata and G. compressa occurred, 

 attached mostly to the larger Sertularians. The " Crumb-of-bread 

 Sponge " {Halichoudria panicea) was not uncommon. Oyster shells, 

 bored by Clione cclata, were seen in thousands. 



\\'hile we were examining the "rubbish," the crew and the 

 Messrs. Rogers were busy with the oyster spat, of which several were 

 found, varying from the size of a pin's head to that of a shirt-button. 

 Often three or four were found on a shell, thus giving promise of 

 a good fall of spat ; a promise which has been fulfilled, for probably 

 there was a larger spat in our Essex rivers last year than in any since 

 1 88 1, but it came late. I heard of as many as forty being counted 

 on a single sh^U from the Blackwater this year, varying from the size 

 of a pin's point to a split pea ; sixteen and seventeen on a shell were 

 not unusual in 1S81. This is rather a shock to Mr. Frank Buck- 



