312 J. W. KIRKALDT. 



Intra-buccal tentacles of the oral sphincter are twelve in 

 number. Oral hood large; tentacles ofthe oral hood twenty- one 

 in small specimens to forty-one in the largest specimens. 

 Olfactory pit present. 



Gonad pouches twenty-three to twenty-nine on the right side, 

 and twenty-one to twenty-eight on the left side (in fifty speci- 

 mens, J. W. K.) ; usually twenty-six on each side. 



Average length of fifty specimens (sent from Naples as well- 

 grown) 4*8 cm. (J. W. K.) ; maximum length 5*8 cm. 



Distribution. — Mediterranean Sea, English Channel, 

 North Sea, coast of Norway. 



2. Amphioxus californiensis, PI. 34, fig. 4. 



Branchiostoma calipoeniense. Cooper. 'Nat. Wealth of Cali- 

 fornia,' 1868, p. 498. 



Myotomes, maximum number 73, minimum number 69, 

 most usual 71 (in ten specimens, J. W. K.). Myotome formula 

 45, 17, 9 (J. W. K.) ; 44, 19, 8 (J. W. K.) ; 44, 16, 9 (Cooper's 

 type-specimen, J. W. K.). 



Dorsal fin of moderate height; series of dorsal fin-ray 

 chambers extending from the eye-spot to the anal myotome. 

 Rostral fin very small. Caudal expansions of the dorsal and 

 ventral fins long and shallow. Ventral fin with fin-ray 

 chambers and paired fin-rays. Anterior extremity of notochord 

 dipping downwards. Oral hood and circlet of tentacles 

 relatively small in size. Gonad pouches, thirty-one right and 

 thirty-one left. 



Oral sphincter underlies the apex of myotome 4. Maximum 

 length of ten specimens 7*4 cm. (J. W. K.). 



Distribution. — Coast of California. 



Remarks. — This species comes nearest to the B. elongatum 

 of Sundevall, the specimens of which are lost. It may be 

 recognised by the relatively small size of the cephalic region ; 

 the oral sphincter is placed far forward (myotome 4), and the 

 anus is placed far backward (myotome 62). 



