LEPTOCAEDIA 



673 



familiar name of the animal ever since. Johannes Miiller (1842) recog- 

 nized its relation to vertebrates, and Kowalevsky (1867) described its 

 embryology and elucidated its relationship to tunicates. 



The Leptocardia are found in shallow bays in many places in tropical 

 and temperate regions, and bury themselves in an upright position in the 

 sand with the mouth projecting into the water. In America they are 

 found as far north as Chesapeake Bay and in Europe as far as Scandi- 

 navia. The class contains a single family and about a dozen species. 



FAMILY BEANCHIOSTOMIDAE. 



With the characteristics of the class: 3 genera. 



1. BRANCHIOSTOMA Costa (Amphioxus Yarrell). Body symmetrical; 

 genital organs on both sides; caudal fin lanceolate: 7 species. 



B. lanceolatum 



(Pallas) (Fig. 1,016). 

 Length about 48 mm.; 

 gonads about 26 pairs: 

 Chesapeake Bay and 

 southerly; Europe; 

 Ceylon. , 6 B ^ 



B. caribbaeum Sun- 

 devall. Length 40 

 mm.; gonads about 26 

 pairs; differs from B. 

 lanceolatum in the slight development of the caudal fin and the short- 

 ness of the postanal region: West Indies, North and South America. 



B. calif orniense Cooper. Length 70 mm.; gonads 31 pairs; cephalic 

 region small : California. 



2. ASYMMETRON Andrews. Body 

 asymmetrical; gonads on right side 

 only; ventral fin with no fin rays and 

 poorly developed; a long caudal proc- 

 ess present : 7 species. 



A. lucayanum* And. Length 13 



mm.; gonads 29 in number, extending from myotomes 15 to 43 inclu- 

 sive; olfactory pit wanting: Bahamas; Zanzibar. 



A. macricaudatum Parker (Fig. 1,017). Length 14 mm.; number of 

 gonads about 26, extending from myotomes 11 to 37 inclusive: Florida 

 coast. 



Fig. 1,016 BrancJiiostoma lancelatum,. A, ventral 

 aspect; B, left side of body (Cambridge Natural His- 

 tory). 1, oral cirri; 2, muscle segments; 3, dorsal 

 fin ; 4, ventral pore of peribranchial chamber ; 5, anus ; 

 6, gonads ; 7, ventral fin. 



Fig. 1,017 Asymmetron lucayanum 

 left side of tail (Parker). 



* See "An Undescribed Acraniate," etc., by E. A. Andrews, Stud. Blol. Lab., 

 Johns Hop. Univ., Vol. 5, p. 213, 1893. 



