ON- ASCIDIAXS COLLECTED BY THE TACHT ' GLIMPSE,' 1881. 527 



On the Ascidians collected during tlie Cruise of the Yacht 

 'Glimpse,' 1881. By H. C. Soebt, LL.D., F.R.S., and 

 "W. A. Heedman, D.Sc, F.L.S., Professor of Natural History 

 in University College, Liverpool. 



[Eead June 1, 1882.] 

 (Plates X. & XI.) 



The cruise of the ' Glimpse ' round the South coast of England 

 commenced early in May, and ended in October, 1881. Very 

 little dredging was done from the yacht in the open sea. Nearly 

 all was done in visiter less than 12 fathoms deep, by means of a 

 light but most efficient dredge, 25 inches wide, Avorked by Dr. 

 Sorby himself from the stern of the gig. With a crew of two 

 rowers there was no difficulty in dragging this dredge, which often 

 brought up as much as could be " docked " and lifted into the 

 boat. A new kind of grapple was also used, especially in the 

 early part of the cruise. By thus dredging from a boat, places 

 could be easily examined where nothing could be done from a 

 yacht. Possibly the successful results are to a great extent due 

 to this cause, since certain objects were more abundant in many of 

 the sheltered places than in the more open sea ; and probably some 

 had not been previously explored. Many thousand specimens of 

 Ascidians must have been dredged during the cruise. Compara- 

 tively few specimens of some of the more common species were 

 preserved ; but the individuals of the rarer sorts were retained. 

 All the specimens kept were placed in the hands of Professor 

 Herdmau, who has carefully investigated them and given the 

 scientific descriptions. Dr. Sorby confining himself to certain par- 

 ticulars observed when the animals were alive, and to the general 

 manner of their occurrence. Towards the close of the cruise 

 the relation between the different organisms and the general cha- 

 racter of the bottom in various localities became more and more 

 apparent ; and it therefore seems desirable to give the following 

 particulars : — 



Southampton : sandy niiid, with many dead shells. Cowes : sandy 

 mud. Poole Harbour : extensive mud banks, with intervening channels 

 several fathoms deep, the bottom of which consisted of dead shells and 

 gravel ; it was in these channels that the Ascidians were dredged, along 

 with many sponges &c. Hooters Bay : wide expanse of mud and narrow 

 channels with muddy bottom, but not deep anywhere. Weymouth Bay 

 and Portland Boads : sandy mud and pebbles, with dead shells. Dart- 

 mouth: coarse and finer shingle, with dead shells ; strong tidal current. 

 Torbay : some jmits clean gravel, and others clean sand, washed by wave- 

 actioa. Orwell and Stour : extensive mud banks with relatively deep 



LINN. JOUEX. — ZOOLOGY, VOL. XTI. 39 



