MOLGULA CONCHILEGA. 45 



colour, appears to be more highly organized than it is 

 in most of the species ; it is composed of laminated 

 lobes, which on the external surface appear as two 

 masses ; one, the smaller, is at the ventral margin of 

 the oesophagus, between it and the intestine ; the other, 

 considerably larger, lies against the dorsal margin of 

 the stomach ; these two masses are united and overlie 

 the right or inner side of that organ, entirely con- 

 cealing it when viewed from that aspect. The anus 

 has a simple, smooth, reflected margin. 



The cylindrical organ in connection with the heart 

 is long and well curved ; and the reproductive organs 

 are somewhat irregular in form. 



2. Molgula complanata Alder and Hancock. 

 (Plate XX1T, figs. 1-6 ; and fig. 37 in text.) 



Molgula complanata ALDER & HANCOCK in Ann. Nat. Hist. 



[(4) VI (1870), p. 366]. 



Body much depressed, rather longer than broad, 

 adhering diagonally by nearly the whole length of the 

 left side, covered with sand and small fragments of 

 shell. Apertures at a little distance apart; the branchial 

 towards the margin, the anal about the centre of the 

 disc. Test rather thin, covered with long simple fibrils 

 to which the sand is attached ; under surface very thin 

 and smooth with only a few grains of sand. Mantle 

 transparent, slightly attached to the test, and with 

 strong radiating muscles around the apertures. Ten- 

 tacular filaments simply pinnate. Branchial sac with 

 six folds on the right side and seven on the left ; the 

 [secondary vessels distinct, and the] meshes a good deal 

 convoluted. Intestinal canal forming a single lono- 



o o o 



loop. Liver pale green, folded or laminated. Repro- 

 ductive organs composing an oblong-ovate mass on each 

 side; the oviducts turned to the posterior margin. 



Length one third of an inch. 



Hab. [Deep water ?] 



