10 ART. 5. — T. AIDA. 



ovary is single and flat ; it covers tlie lower liiud x^art of 

 testis. 



The tail lias wide muscular bands. No subchordal cells are 

 present. The average ratio of the length of tail to its greatest 

 breadth is 4.8 : 1, and that of its greatest breadth to the width 

 of the musculature is 1.75 : 1. 



The largest specimen I have obtained was 1200 /^ long in 

 trunk and 4060 /i long in tail. 



2. Oikopleura fasifovmis Fol (1872.). 



PI. III., figs. 8-12. 



Buccal gland wanting. Eisen's oikoplast present. 

 Blind sac of the left stomach very large and extends 

 upward and backward after departing from œsophagus. 

 Bight stomach small, continuous with the small ante- 

 rior and upper part of the left stomach. Spiracles 

 widely separated from the endostyle. Genital glands 

 cover the lateral side of the alimentary canal. Ovary 

 simple and flat; testis paired. Tail with narrow 

 muscular coating and without subchordal cells. 



The trunk is elongate and its upper margin is nearly straight. 

 Mouth shifted to the dorsal aspect of trunk. 



The oikoplast epithelium covers only the anterior branchial 

 region of the trunk, the greater part of the alimentary canal 

 being free from it (fig 8, PI. III.). The Eisen's oikoplast is 

 cruciform, composad of four cells {j)m., fig. 8). The endostyle 

 is short and widely separated from the atrial canal. 



