THE ASCIDIANS 227 



Ascidia adhterens sp. nov. 



Molgula graphica sp. nov. 



Rhizomolgula arenaria gen. et sp. nov. 



Cynthia villosa Stimpson. 



Styela yakutatensis sp. nov. 



S. truncata sp. nov. 



Distoma pulchra sp. nov. 



Distaplia confusa sp. nov. 



D. occidentalis Ritter. 



Didemnum strangulatum sp. nov. 



Amaroucium translucidum sp. nov. 



A. coei sp. nov. 



A. californicum Ritter. 



Psammaplidium pedunculatum Herdman. 



Botryllus magnus sp. nov. 

 The material, including slides for microscopic study and dis- 

 sected preparations, is in the museum of the University of Cali- 

 fornia ; but, where the number in the collection would permit, 

 specimens of all the species have been placed in the National 

 Museum at Washington. 



ASCIDIA ADHERENS sp. nov. 

 (PI. XXVII, figs. 1-5.) 



General characters. — iVttached so closely by the whole left side 

 that the test on this side is much reduced in quantity and the detach- 

 ment of the animal is made difficult, a peculiarity from which the spe- 

 cies is named. Much flattened, elliptical in outline, generally regular, 

 surface for the most part even and smooth. A considerable number 

 of individuals, usually more or less run together edge to edge, the 

 whole forming a thick encrusting layer. Siphons distinct, particularly 

 in larger individuals, though never long. Lobes of siphons incon- 

 spicuous, though discernible, when orifices are fully expanded, by 

 small darker specks on the margin. Lobes best seen in smaller indi- 

 viduals. Usually seven on the branchial siphon, and six on the atrial ; 

 an occasional individual however, with six and five respectively. 



Branchial siphon situated at the anterior end and on the edge ; the 

 atrial not remote from the branchial on the right upper surface of the 

 animal, somewhat removed from the edge (p1. xxvii, fig. 2). Color 

 entirely white (opalescent), except a tinge of yellow on the siphons, 

 and some deeper yellow in stomach distinctly visible through test. 



