63 



On a Tornaria found in British Seas. 

 By 



Gilbert C. Bourue, II.A., F.l^.S., 



Fellow of New College, Oxford, and Resident Director of the Association, 



With Plates VII, VIII. 



Befoee 1888 DO specimen of Tornaria, the well-known pelagic 

 larva of Balanoglossus, had been taken off the English Coast. But 

 on August 9th of the past year Mr. Weldon, usiug the surface net 

 near the Eddystone Lighthouse, took several young specimens of 

 Tornaria, and subsequently the same gentleman, during a cruise of 

 a week's duration towards the end of August, captured many larger 

 and more mature specimens of the same larva. Other specimens 

 were taken by us up to September 21st, and in the month of 

 August Mr. Rupert Yallentin found several specimens in the vicinity 

 of Falmouth. 



The specimens taken on these occasions form the subject of the 

 present memoir, and their anatomy is detailed at some length, both 

 because of the interest attached to a form hitherto unknown to 

 England, and because it is in some respects of morphological im- 

 portance. 



The specimens taken by us came from the offing, and were not 

 taken within four miles of the shore ; Mr. Vallentin's Tornaria 

 were found close to the shore at Falmouth. As he was able to 

 bring his back alive and preserve them at leisure in his laboratory, 

 they are better preserved than those taken by us, since we were 

 obliged to preserve our catch in a somewhat rough manner out at 

 sea. An examination of Mr. Vallentin's specimens leaves me no 

 doubt that the larva is Tornaria Krohnii, a species found in the 

 Mediterranean. The different forms of Tornaria have not been with 

 certainty referred to their adult forms, but T. Krohnii must belong 

 to one of the Mediterranean species of Balanoglossus, that is to say, 

 to B. KowalevsTiii, B. minntiis, or B. claviger, species which have not 

 hitherto been recorded from the English Channel, unless we suppose 

 that the larva of B. salmoneus v. sarniensis, which occurs in the 

 Channel Islands and at Roscoff, is identical with Tornaria Krohnii. 



The larvae found on August 9th were of minute size, the largest 



