MOLGULA VALVATA. 51 



eyes looking through spectacles. The external fibrils, 

 too, are very different ; in M. valrata- they are extremely 

 delicate and hair-like, and are much contorted and 

 confused ; but in M. oculutn they are stout, and, though 

 twisted and ano-ulated, can be easily traced. And 



O t 



again in the latter the mantle is strongly adherent to 

 the test, while in M. ralrata (PI. XXV, fig. 1) it is, as 

 usual, entirely free except at the tubes. 



5. Molgula simplex Alder & Hancock. 

 (PI. XXV, figs. 2 and 3; and figs. 40 and 41 in text.) 



Molgula simplex- ALDER & HANCOCK in Ann. Nat. Hist. 

 [(4) VI (1870), p. 365]. 



Body globular, sub-pellucid, nearly smooth, free, or 

 very slightly attached. Apertures nearly terminal, not 

 far apart, slightly tubular and retractile. Test rather 

 soft but tough, generally rather thinly clothed with 

 linear fibrils, which are rarely forked, and seldom have 

 any sand or shell adhering to them. Tentacular fila- 

 ments branched, irregularly tripinnate, about eleven in 

 number with minute ones interspersed. Branchial xnc 

 with six folds on each side, the meshes distinctly but 

 irregularly convoluted. Oral lamina smooth, broad 

 below. Intestine forming two loops confined to the 

 lower half of the sac. Reproductive organs forming a 

 slightly arched mass on each side, with the margins 

 divided into narrow irregular lobes, that of the right 

 side within the lower intestinal loop. 



Diameter one-half to three-quarters of an inch. 



Hab.? 



ENGLAND. --Torbay, Devon, and Plymouth, Corn- 

 wall (Abler). 



SCOTLAND. Oban, Argyll (Alder). 



IRELAND. Strangford Lough, Antrim, and Bally- 

 waiter, Down (Thompson). 



First record. 'Alder & Hancock, ] 870. 



