STYELA HUMILIS. 117 



shallow folds on each side, the meshes elliptical, in 

 rather distant rows. 



Length nearly an inch. 



Hal). Adhering to nullipores. 



CHANNEL ISLANDS. St. Peter's Port, Guernsey; 

 dredged (Alder}. 



First record. [Ansted, 1862; coll. Alder.] 



The test of 8. humllis (PI. XXXIX, fig. 7) is cori- 

 aceous with a metallic lustre inside. The mantle is 

 thin and firmly attached to the test. 



The branchial folds are much narrower than usual ; 

 the 1 primary vessels, which are rather large, are regu- 

 larly disposed, and have a minute vessel between them 

 which crosses the stomata. The stomata are fusiform 

 with the extremities pointed ; they do not reach from 

 vessel to vessel, and their rows are consequently further 

 apart than is usual ; there are widish spaces bordering 

 the primary vessels. The longitudinal rods are wide, 

 with the thickened free margin stout ; there are four 

 or five on the folds, and three or four between them. 

 The oral lamina is smooth and moderately developed ; 

 the branchial tubercle (PL XL VIII, fig. 13) is small. 



The alimentary canal is short and looped ; the 

 stomach is rounded and its interior is laminated. 



The reproductive organs are composed of numerous 

 oval or rounded nodules. 



This species has considerable resemblance to Styela 

 comata in most of its characters, but is at once distin- 

 guished from it by the position of the apertures, which 

 in $. hum His are more widely apart than in any other 

 species of the genus, while in S. comata they are close 

 together at the upper end. S. humilis also is attached. 



11. Styela variabilis s/>. nor. 



(PL XXXVII, figs. 10-12 ; PL XLIII, fig. 1 ; PL 



XL VIII, fig. 14.) 



Body variable in form, ovate, sub-orbicular, or sub- 

 conical, and strongly wrinkled in opposite directions 



