62 BRITISH TUNICATA. 



9. Molgula citrina Alder & Hancock. 



(PI. XXVI, figs. 5-9; PI. XXVII, figs. 6-8; PI. 

 XXVIII, figs. 3-5 ; PI. XL, fig. 4; PI. XL VIII, 



fig. 3 ; and figs. 46 and 47 in text.) 



Molgula citrina ALDER & HANCOCK in Trans. Tyneside 

 Nat, Field Club, I [1848], p. 198; [COCKS in Rep. E. 

 Cornw. Polyt. Soc. 1849 (1850), p. 73; NORMAN in Rep. 

 Brit, Assoc. for 1868 (1869), p. 303]. 



Bod)/ transversely ovate, convex, attached by a 



' / *.- 



broad base. Apertures, branchial sub-terminal, slightly 

 tubular, divided into six pointed segments, a little 

 everted when open ; anal about one-third down the 

 body on the upper side, sub-tubular, smaller than the 

 branchial, and divided into four less-pointed segments. 

 Test nearly smooth, greenish yellow, semitransparent, 

 deeper yellow or orange-coloured at the lower end, 

 from the viscera showing through. Mantle smooth, 

 yellow. Tentacular filaments pinnate. Branchial sac 

 with seven folds on each side; the vessels irregularly 

 convoluted in a double spiral, the spirals in the folds 

 distinct, paired. Oral lamina narrow, not widened at 

 the mouth. Intestine in a single loop. Reproductive 

 organs large, wide, irregularly-formed masses. 



Length three-eighths to half an inch. 



Hal). On the underside of stones between tide 

 marks [and at low water]. 



ENGLAND. Cullercoats (Alder ty Hancock) and 

 Bamborough (Alder), Northumb. "Wliitburn, Durham 

 (Alder). Douglas, Isle of Man (Alder). [Helford 

 River, Falmouth, Cornwall; in trawl refuse (Cocks). ~\ 



SCOTLAND. [Lerwick, Shetland, at low water, 1861 

 (Norman).] 



First record. Alder & Hancock, 1848. 



The mantle of this species (PI. XXVII, figs. 6 and 7) 

 is quite diaphanous, though somewhat thickened in the 

 region of the tubes ; the radiating muscles are long 

 and delicate, passing more than half way down the sac. 



