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XIII. — Report upon the Tunicata dredged during the Cruises of H.M.SS. 

 "Porcupine " and "Lightning,' 1 '' in the Summers of 1868, 1869, and 1870. 

 By W. A. Herd man, D.Sc, Professor of Natural History in University 

 College, Liverpool. (Plates XXXV. and XXXVI.) 



(Read 7tli January 1884. ) 



A few years ago the late Sir C. Wyville Thomson gave me for examination 

 some specimens of Ascidians which had been obtained during the cruises of 

 the "Porcupine" and "Lightning," and last summer I received from Mr John 

 Murray the remainder of the Ascidise Simplices and two species of the 

 Ascidise Compositae from the same deep-sea dredging expeditions.* Some 

 additional specimens of the " Porcupine " Ascidiae Compositae have been placed 

 in my hands during the last few days (January 1, 1884). The present paper 

 contains a detailed account of the Simple Ascidians alone; the Compoum 

 forms will be worked up along with the "Challenger" Ascidise Compositae, 

 and will be described and figured in the second part of my Report upon the 

 Tunicata of the "Challenger" Expedition. It may, however, be useful to 

 state here that the " Porcupine " Compound Ascidians include : — 



Distaplia rosea, Delia Valle. 



One colony from Tangier Bay ; 35 fathoms. 



Aplidium falkuc, Johnston. 



Two small colonies from Loch Foyle ; 10 fathoms. 



Leptoclinum, sp. 



One colony from Station 12 ("Lightning," 1868, Faeroe channel) ; 530 

 fathoms. 



Leptoclinum, sp. 



Several colonies ; locality unknown. 



Leptoclinum albidum. 



Several colonies from Tangier Bay ; 35 fathoms. 



* In the summer of 1868 H.M.S. "Lightning" explored the region of the North Atlantic lying 

 between the Hebrides and the Faeroes. In 1869 H.M.S. "Porcupine " made three cruises, the first off 

 the north-west and west coasts of Ireland, the second off the south and south-west of Ireland, and the 

 third off the north of Scotland as far as the Faeroes. In 1 870 the " Porcupine " dredged down the 

 west coasts of France and Spain and in the neighbourhood of Gibraltar Strait, and explored the African 

 coast of the Mediterranean as far east as Sicily. 



VOL. XXXII. PART II. 2 N 



