68 University of California Publications in Zoology. [ VoL - 6 



Branchial Apparatus:- -Siphons, particularly as seen after 

 removal of the test, typically, though by no means universally, 

 of good length, frequently lout: and slender. PL 7. figs. 1 and 

 V. I Branchial generally broader a1 lias.- and somewhat more ter- 

 minal as to the long axis of the animal -. orifices of both positively 

 quadrangular, color of lobes with alternating red and white 

 spcits or areas. Tentacles varying in number from 17 to 62 

 (see tables), of very unequal size, compound. Hypophysis, typ- 

 ically horseshoe shaped, the two ends turned in more or less. 

 but various deviations from the type. I PL 10, figs. 1 to 29. left 

 column. I Ganglion, rather narrow, close behind the hypophysis. 

 Dorsal Languets: — Generally rather long and slender, regu- 

 lar, varying in number from 4:> to l s 7 (see table). Branchial 

 membrane with six folds on each side, fourth from the endostyle 

 usually largest, having maximum of 29 longitudinal vessels, the 

 first from endostyle smallest with maximum of 24 vessels see 

 table . Transverse vessels also present, of different sizes, usually 

 about six stigmata between each two longitudinal vessels: for 

 purposes of description these designated as "long" and "short" 

 see table i. 



Intestinal Tract: — Situated on left side of the body, loop 

 wide, the great bend reaching* far forward, rectal limb with flex- 

 ure, amis with a thickened edge, variously lobed and notched; 

 (PL 10, figs. 1-29. right column). Stomach somewhat, though 

 but little, greater in diameter than intestine, with typically three 

 folds on inner aspect, the middle one largesl PL 8). Liver 

 a brownish-yellow organ in the form of a bunch of grapes, open- 

 ing by a short, wide duct into the distal end of the stomach, the 

 eland itself lying between the stomach and the return limb of 

 the intestine: some of the lobes closely adherent, probably by 

 blood-vessels, to the outer surface of the branchial membrane. 

 "Lacteal" system presenting a number of irregular lobes pro- 

 jecting conspicuously along the great bend of the intestine i PL 

 8, fig. 3). 



Ii'i jiriiilin tin Organs: — < >n both sides of the body, those of 

 left in the intestinal loop, consisting of a double series of more 

 or less regular, pear-shaped lobes placed close together along 

 each side of the axial duct with which all communicate (PL 8, 



