92 



7he Irish Naturalist. May 



BRITISH AND IRISH TUNICATES. 



The British Tunicata. An unfinished Monograph. By Joshua Alder 

 and Albany Hancock, Edited by John Hopkinson, F.L.S., F.G.S., 

 Vol. iii. Aggrcgatae (Ascidiae Compositac). Pp. xii. + 114. 

 Plates li. — Ixvi., and frontispiece. London ; Ray Society, 1912. 

 Price I2S. 6d. net. 



The issue of this volume brings the chequered history of this ' unfinished 

 Monograph ' to a happy ending, so far as the systematic portion of the 

 work is concerned. A fourth volume, by the Editor, will supply a Biblio- 

 graphy of the Tunicata, and will probably be some consolation to students 

 of this group, to whom tlie publication of the Monograph can hardly be 

 an unmixed blessing. A brief account of its history was given in the 

 review^ of the second volume. The present volume deals with the Com- 

 pound Tunicates found in the littoral and shallow waters of the British 

 Isles. The pelagic species (Oikopleura, Salpa, Pyrosoma, &c.) were not 

 dealt with by Alder and Hancock. Our knowledge of these forms is of 

 comparatively recent date, though they form a by no means unimportant 

 constituent of the oceanic plankton. 



The Compound Tunicates, which form a conspicuous • and beautiful 

 feature in the littoral fauna, present to the systematist such great diffi- 

 culties that they have unfortunately received less attention than they 

 deserve. Their sedentary mode of life, and habit of forming shapeless 

 encrusting colonies on stones and sea-weeds, result in such great variation 

 in external characters, that careful examination and laborious dissection 

 are necessary to determine the species. To these difficulties is added the 

 absence of any modern Monograph dealing with the group. The present 

 volume will to a limited extent fill this gap, and the Editor has wisely 

 supplemented the drawings left by the authors with figures taken from 

 the well-known works of Milne -Edwards and Savigny. At the present 

 day, there seems to be no student of the Tunicata in the British Isles, 

 and if this Monograph stimulates interest in such an interesting and 

 important group, it will not have been issued in vain. 



Fifty-three species are described, included in ten genera and three 

 families. In the nomenclature of the present day, the number of species 

 would probably be greatly reduced, Avhilst that of the genera and families 

 would be increased. A critical revision of all the species described in 

 this Monograph is greatly to be desired. In addition to 135 text-figures, 

 the species are illustrated by 16 coloured plates. A number of species 

 are recorded from Ireland, collected by Thompson, Dickie, Canon Norman, 

 &c. It is of interest to note that Canon Norman, whose portrait forms 

 the frontispiece to the present volume, collected Tunicata in Bantry Bay 

 so long ago as the year 1858. 



R. S. 



^ Irish Naturalist, vol. xvi., 1907, p. 365. 



