364 EDWARD S. MORSE ON 



In T. septent7^ionalis, the nephridia are suspended from the gastro-parietal band on each 

 side of the intestine, with the nephrostomes opening toward the dorsal shell (56 : 2) . This 

 figure represents the right nephridium with a portion of the intestine and the divaricator 

 muscles. The band, by which the nephrostomes are held, stretches across the coelomic 

 chamber and adheres to the intestine as well. In 56 : 1, is shown the left nephridium in 

 profile. The nephrostome is wide, and within, the surface is thrown into a number 

 of irregular folds which on one side gradually merge into papillae. Two of these are shown 

 more highly magnified, within which may be seen the ciliary ridge (56 : 2a) . The agaric- 

 hke regularity of these folds, as figured by Hancock, in T. caput-serpentis, is not observed 

 in T. septentrionalis, at least in its living state, and I may add also that Hancock represents 

 the nephrostomes as quite close together, while in T. septeritrionalis they are widely sepa- 

 rated from each other, as may be seen in 60: 1. This peculiarity adds another distinction 

 justifying the separation of the two species. The body of the nephridium has a rich brown- 

 ish-yellow color (39:9), and is marked by varicose ridges; the surface, more highly 

 magnified, shows very irregular markings, transverse to the long diameter of the tube 

 (56: 2b, 2c). The nephridial tubes viewed in front through the coelomic wall (60: 1, 2), 

 run nearly parallel and turning abruptly, pierce the wall and project beyond in the form 

 of prominent nipples (56: 7) . Dall (71) describes the external openings of the nephridia 

 in Dallina jloridana as teat-shaped with very small orifices. Doubtless in related forms 

 this protuberant end will be found, though in Terebratalia coreanica, as we shall see, it is 

 in the form of a simple slit in the parietes. The appearance of the orifice in the nephri- 

 dium of T. septentrionalis, viewed directly in front, is shown in 56 : 6. The nipple is 

 nearly circular, the larger diameter being vertical ; the opening is circular and an indica- 

 tion of a lozenge-shaped escutcheon is seen surrounding the orifice, this appearance arising 

 from muscle fibers which possibly control the orifice. The interior of the opening, as well 

 as the channel within, is strongly ciliated. It will be seen in 56: 1, 2, that a band, or bands, 

 quite separate from the ilio-parietal band, originate at the edge of the nephrostome and 

 run ventrally ; upon this is found the accessory vesicle as well as clusters of ova. This is 

 the genital band and is well shown in 56 : 1. In 60 : 1, the attitude of the nephridia in 

 relation to the mouth and brachia is shown. In 56 : 4, 5, the appearance of the nephridia in 

 very young specimens is given. The flaring edge of the nephrostome instead of being 1am- 

 ellated has a distinct, thickened rim ; the rim of the nephrostome seems to be interrupted, 

 as if its attachment were like that seen in L. lepidula, that is, that the band, or wall to which 

 it is attached, forms part of the boundary of the nephrostome. In T. coreanica, viewed 

 from the dorsal surface (55 : 8) , the nephrostomes open obliquely backward. The inner 

 surface is marked by thin, sharp, radiating folds which in appearance suggest the actinoid 

 coral, Fungia (55 : 9) . The folds are vertically marked or plicated. A slight constriction 



