GENBRAL ZOOLOGY. 41 



The width of the Lord Howe fringiug reef is very variable, and in con- 

 sequence its distance from the shore equally so. It is however, from one to 

 three-quarters of a mile, but as the bottom of the Lagoon shoals very 

 gradually this is perhaps to be accounted for. The depth of the channels 

 passing through the reef differs much. The main north-west entrance varies 

 from a little less than four to six fathoms. The south entrance im- 

 mediately in the gut-way has six and seven fathoms of water, outside in- 

 creasing to nine, whilst just inside the Lagoon it shoals to two and a quarter 

 fathoms. 



The Lagoon wherever examined by us showed a sandy bottom, except off 

 the " Old Settlement," where it becomes rather more argillaceous. We 

 anticipated finding it teeming with life, but it proved very barren, and com- 

 paratively destitute of isolated coral growth. The coral life of Lord Howe 

 Island was one of the points to which we were least able to pay satisfactory 

 attention, and will afford a wide field of inquiry for future researches. 



Hydrozoa. — 'Like the Actinozoa this group required a much larger amount 

 of time than we were able to afford for its study. The specimens obtained 

 were chiefly collected from weed thrown up on the sandy beach of the 

 Lagoon. One very important discovery, however, was made by Mr. 

 Whitelegge, namely, CeretelJafasca, Gray, with the polypes protruded, and 

 which by very careful manipulation he was able to kill in that condition. 

 I believe I am correct in stating that the zooids of this hydrozoon have 

 not before been observed. 



The Siplionoi)liora are very plentifully represented by jPhysalia and Velella. 

 At certain times the Lagoon beach is simply covered by myriads of the 

 Fh/salia megalisfa, Brandt ; but what is very singular, on those days on 

 which the Velella is washed ashore in equal quantities, Fhysalia is entirely 

 absent. The stinging properties of P. megalista are very powerful. Not 

 only is intense inconvenience caused to the part brought in contact wth 

 the animal — say, for instance, the hand — but the irritation so caused can be 

 conveyed from that member to any other part of the person touched, such 

 as the face. Although losing the beautiful dark purple-ultramarine blue 

 Avhen placed in spirit, the bladder retains this tint for a considerable time, in 

 more or less perfection, when left lying on the sandy beach. 



The remaining Hydroids collected, as determined by Mr. "Whitelegge, 

 are : — 



Ceratella f usca. Gray ? 

 Sertularella solidula, Bale. 

 Eucopella campanula, Lendfel. 

 Sertularia minima, D'A. W. Thompson. 

 Halicornaria, sji. nov. ? 

 Halicornaria, sp. nov. ? 

 Plumularia, sp. nov. ? 

 Plumularia spinosa. Bale. 

 Campanularia tincta, HincTcs. 



Porifera. — Of large sponges but few were obtained, and these wholly as 

 dead specimens. The blocks and stones about the reef foster several forms 

 of small incrusting sponge which would probably repay study. 



The determinations so far, made by Mr. T. Whitelegge, are as follows: — 



lantheila flabelliformis. Gray. 



Cacospongia, sj). 



Euspongia officinalis, Linn., vars. 



