264 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Styela joannce,* n. sp. PI. XIII., figs. 5 — 9. 



External appearance. — Shape swollen ovate, approach- 

 ing globular, attached by a large area on left side, which 

 is expanded at its edge to form a well-marked basal plate. 

 Posterior end wide, anterior end narrower, and bearing 

 both the apertures rather close together. They are both 

 slightly prominent and 4-lobed, so as to have regularly 

 cross-slits. Surface perfectly smooth. Colour whitish 

 grey. Length 2*3 cm., breadth 2 cm., thickness 8 mm. 



Test very thin, and semi-transparent, but rather tough. 

 Thicker aud stirler on the left side over the large area of 

 attachment. 



Mantle thin, musculature very delicate. Well-marked 

 sphincters on the siphons. 



Branchial sac with 4 well-marked but narrow folds on 

 each side. There are about 6 internal longitudinal bars 

 on each fold, and 4 in the interspace. The transverse 

 vessels differ in size — three sizes alternating with fair 

 regularity. Meshes transversely elongated, containing 6 

 to 8 stigmata, which are rather. straight and wide. Meshes 

 occasionally divided by a narrow horizontal membrane. 



Dorsal lamina a plain narrow membrane. 



Tentacles long and slender, closely placed, about 40 in 

 number. 



Dorsal tubercle simple, horse-shoe shaped or cordate, 

 with horns turned in. 



Stomach elongated and curved, with many longitudinal 

 grooves. Intestine with a narrow loop. 



Gonads in the form of several long slender tubes, 7 on 

 the right side and 8 on the left. A circle of from 30 to 40 

 minute atrial tentacles is present. 



* I venture to name this species after my wife, who accompanied me on 

 the dredging expeditions, and, as usual, gave me much help in collecting, 

 preserving and packing the specimens. 



