SOLMISSUS INCISA. 69 



tion ; but in all Fewkes's specimens the gastric wall was entirely torn away, 

 so that since he was ignorant of the true interpretation of the subumbral 

 prominences which he describes on the gelatinous disc, he had no direct evi- 

 dence on this point. It seems to me, however, that the occurrence of eleva- 

 tions in the radii of the tentacles shows conclusively that gastric pockets did 

 exist, inasmuch as these elevations are exactly the same structures which 

 occur in the regions of the gastric pockets and cause their convexities in 

 8. marshalli. The radial furrows which Fewkes observed alternating with 

 the prominences occur in the present specimens also, and occupy the septal 

 regions between the pockets ; while the " white structure " ('89 a , p. 529) which 

 he found lining certain of these furrows, is nothing more than a portion 

 of the gastric wall persisting in these regions, as I have often found it ; al- 

 though destroyed elsewhere. It is the same structure which Agassiz and 

 Mayer (: 02) mistook for gonads in S. marshalli. In short, Fewkes's specimens 

 showed exactly the appearance of those in the present collection in which 

 the subumbral gastric wall is entirely torn away. In such characters as may 

 be considered of specific importance the agreement between the Pacific and 

 Gulf Stream specimens is close. Thus, in both the number of tentacles is 

 large, and the maximum in each appears to be thirty-two; in both a very 

 large diameter, 100 mm. or more, is attained ; in both the gelatinous disc is 

 thin, soft, and very fragile ; and both show the same tendency to split along 

 or between the peroniae, so as to divide the marginal zone into separate 

 lappets. Since Fewkes was unable to distinguish the octocysts in any of his 

 specimens, it is very desirable that fresh specimens from the Gulf Stream 

 be examined, the number of octocysts being probably of specific importance 

 in this genus. 



The status of Haeckel's (79) two species is doubtful, since his descrip- 

 tions are so brief and lacking in detail that the only characters on which 

 we can rely are size and the number of tentacles. He has mentioned the 

 number of otocysts per lappet, but since each species was described from a 

 single alcoholic specimen, I do not believe his counts of the otocysts (he found 

 three per lappet in 8. faberi and one per lappet in S. bleekii) can be relied on fur- 

 ther than to show that in both, as in the present specimens, the number of 

 these organs is rather small. S. faberi is 20 mm. in diameter with twenty-four 

 tentacles; S. bleekii 40 mm. in diameter with thirty-two tentacles. The 

 differences between the two are, then, no greater than occur between dif- 

 ferent specimens of the present species, or of S. marshallii, and ran be 



