8 University of Michigan 



seven counts, 289) ; preanal fin chambers, 36 to 48 (average 

 of four, 41). Highest dorsal ray-chambers two to four times 

 as high as long; dorsal fin about one-eighth as high as body. 

 Anus located near middle of lower lobe of caudal fin ; distance 

 from atriopore to origin of lower caudal lobe about equal to 

 distance thence to tip of tail. Postanal length, 13.8 to 17.4 in 

 total. Preatrioporal length, 2.3 to 2.7 (usually about 2.5) times 

 the postatrioporal length. Myotome formula: 32 to 36-I-14 

 to 17+7 to 10=57 to 61 (about twenty-five Florida specimens 

 counted by the writer and Andrews). Gonads 22 to 27 on 

 each side, usually about 25. Maximum length, 6.1 cm. 



8. Branchiostoma virginiae Hubbs, new species 

 Branchiostoma lanceolatum Andrews (1893, Chesapeake Bay speci- 

 mens onh'). 



Type-material: — Holotype, Cat. No. 84465, U. S. National 

 Museum, from Sewall's Point, Virginia, on Chesapeake Bay. 

 Paratypes with same data. Another specimen was collected 

 in Chesapeake Bay in Mar}dand along the east shore. 



Status: — The lancelet of Chesapeake Bay appears to differ 

 from the other American species of the genus in the increased 

 number of myotomes. In this respect it resembles the European 

 B. lanceolatum, from which in turn it is distinguished by the 

 more posterior position of the anus in reference to the lower 

 lobe of the caudal, the relatively shorter distance between this 

 fin lobe and the atriopore and the more numerous dorsal ray- 

 chambers. It is more closely related to iioridae than to lance- 

 olatum. All of the lancelets from the East Coast of the United 

 States, variously referred to lanceolatmn or caribaemn, are 

 perhaps conspecific with the Chesapeake form. It seems not 

 improbable that virginiae and Uoridac will be found to 

 intergrade. 



Diagnosis: — Dorsal ray-chambers, 259 to 309 (average of 



