Fishes of the Western North Atlantic 13 



rapidly about for a short time if the temperature be either raised or lowered. If heated to 

 40° C. or higher they diej if chilled to 10° C. they become inactive and may die, as they 

 invariably do if kept in a temperature of 4° C. for half an hour. But the thermal reactions 

 are not known for specimens adapted to the winter temperatures that prevail at Bermuda. 



It has been found that B. berniudae tends to swim away from a source of light; also it 

 is stimulated to activity by the presence of light, «.<?., it is photokinetic," and hence it may 

 be expected to bore deeper into the sand if strongly illuminated, as by the sun. But it is more 

 sensitive to mechanical than to photic stimulation, as is the European B. lanceolatum.^* 

 This is especially true of the preoral tentacles and of the outer fringes of the oral hood, 

 which close and open with a sudden winking motion if touched. It is through this reac- 

 tion that the Lancelet rids itself of the debris that may accumulate on its preoral tentacles, 

 for when these become laden they contract sharply to loosen any waste particles, which 

 are then swept away by water that is expelled simultaneously from the cavity of the oral 

 hood. 



Presumably it spawns chiefly in late spring, for the peak of the breeding season is 

 passed before June-July. 



Range. Bermuda. 



Synonyms and References: 



Branckiostoma lubricum Goode, Amer. J. Sci., 14, 1877: 293 (Bermuda); not B. lubricum Costa, 1834. 



Amfhioxus (no specific name) Brooks, 3rd Annu. Rep. Johns Hopk. Univ., 1878: 54 (Bermuda). 



Branchiosloma caribaeum Bristol and Carpenter, Science, N.S. //, 1900: 170 (Bermuda); \'errlll. Trans. 

 Conn. Acad. Arts Sci., 11, 1901: 55 (Bermuda); Bean, Field Mus. Publ. Zool., 7 (2), 1906: 29 (Ber- 

 muda); Kutchin, Proc. Amer. Acad. Arts Sci., ./p (10), 1913: 571 (peripheral nervous system). 



Amfhioxus caribaeu! Mark, Science, N.S. 20, 1904: 179 (Bermuda). 



Branchloitoma caribhacum Barbour, Bull. Mus. comp. Zool. Harv., 46, 1905: 1 10 in part (specimen from Ber- 

 muda) ; Parker, Proc. Amer. Acad. Arts Sci., 4^ ( 16), 1908; 413 (sensory reactions, Bermuda) ; Arey, J. 

 exp. Zool., 2p (i), 1915: 37 (swimming habits, Bermuda). 



Branchiosloma carribaeum Mark and Crozier, Anat. Rec, 11 (6), 1917: 520 (photo receptors); Conklin, J. 

 Morph., 54 (l), 1932: 70 (breeding season at Bermuda); not B. caribaeum Sundevall, 1853. 



Branchiosloma bermudae Hubbs, Occ. Pap. Mus. Zool. Univ. Mich., 105, 1922: 9 (descr., discus., Bermuda) ; 

 Jordan, Evcrmann and Clark, Rep. U. S. Comm. Fish. (1928), 2, 1930: 7 (Bermuda); Becbe .ind 

 Tec-Van, Field Bk. Shore Fish. Bermada, 1933: 2 (descr., ill., Bermuda); Goldschmidt, Biol. Bull. 

 Wood's Hole, 64 (3), 1933: 321 (Bermuda) ; Pratt, Manual Common Invert. Anim., 1935: 757 (no. of 

 myotomes and gonads, Bermuda) . 



Branchiostoma caribaeum Sundevall, 1853 



Figure 2 E 



Study Material. Numerous specimens, 12 to 66 mm. long, from Maryland, Chesa- 

 peake Bay, Virginia, North Carolina, eastern and western Florida, the Tortugas, Florida, 

 and Vieques Island, Porto Rico. 



13. Parker, Proc. Amer. Acad. Arts Sci., 4} (16), 1908: 426. 

 24. Franz, Wiss. Meeresuntersuch. Helgoland, 15 (14), i924'- 6. 



