2 University of Michigan 



more complete comparisons thus made possible necessitate 

 almost doubling the number of species of Branchiostoma. Four 

 of the five new forms described, inhabiting the Western Atlan- 

 tic, have heretofore been confounded with Branchiostoma 

 caribaciim or B. lanceolatum. 



II 



This survey of the lancelets has indicated that the lancelets 

 are about as localized in their distribution as are the species 

 of littoral teleosts. This statement may be illustrated by a 

 geographical tabulation of the species of Branchiostoma, to 

 which unusually wide ranges have frequently been attributed. 

 This genus is chosen because it has been most critically studied ; 

 the species of the other genera of the lancelets are likewise of 

 localized distribution. 



Table indicatiny the distribution of the knozmi species of 

 Branchiostoma 



SPECIES REGIONS INHABITED 



B. lanceolatum Pallas European and Indian ( ?) 



B. belcheri Gray Indo-asiatic 



B. caribaemn Sundevall Antillean 



B. iioridae Hubbs Floridan 



B. virginiae Hubbs Carolinan 



B. bermiidae Hubbs Bermudan 



B. platae Hubbs Patagonian 



B. calif orniense Andrews Californian and Panamaic 



B. tatter salli Hubbs Indian 



B. capense Gilchrist Cape 



B. elongatum Sundevall Chilean, Peruvian, Galapagoan 



The genus Branchiostoma is known from nearly all tropical 

 and temperate seas; Dolicharhamphus is Indian (one species 

 known) ; the unsymmetrical lancelets, Epigonichthys and 

 Asymmetron, are chiefly Indo-australasian in distribution, but 

 Asymmetron occurs also in the western Atlantic. 



