1897.] NEW YORK ACADEMY OF SCIENCES. 221 



port. Either there are two Heteronereid forms or, as Wirfen states, 

 the last named is not a form of N. facata but of N. zonata* 



Number of segments is 94, first included, which as is usual lacks feet and 

 bristles. The 22 bristle-bearing segments completely unchanged in respect 

 to form of foot parts and relative size and to nature and distribution of 

 bristles. (There are 27 in N. cydurus.) 



Seven first bristle-bearing somites with, as is usual with males, the lower 

 part of dorsal cirrus somewhat, though slightly, thickened. From the 24th 

 segment, feet suddenly changed and in same manner as with most species 

 when they reach maturity. Upper division of foot furnished with 3 blade- 

 shaped appendages. The first rounded trapezoid, behind the base of dorsal 

 cirrus. The second and third oblong, the upper being fastened behind 

 bristles of upper foot branch, the lower under bristles but fastened on front 

 side of foot branch. On upper lobe of foot branch, the hinder lamella grown 

 out to a kidney shaped blade which reaches outside the points of bristles. 

 Front lamella also somewhat enlarged. Lower lobe thickened and sharply 

 shut off from upper by deep furrow. Dorsal cirrus bearing on under side ^ 

 wart-shaped papillae of which 2-3 are somewhat larger than the rest. Ven- 

 tral cirrus unchanged, but from its base there is developed on upper side 

 a cylindrical appendage furnished with annular constrictions and on under 

 side, a kidney-shaped or semicircular blade. ( Compare Plate XVIII, fig. 5 of 

 N. cydurus, which does not show dorsal accessory blades. Many of these must 

 have swimming function. ) All the blade-shaped appendages of the feet are 

 unusually large, especially the large blade of lower foot, in comparison with 

 other epitocous Nereis forms. 



Bristles exceedingly numerous — placed in several rows in front of each 

 other and all knife or oar-shaped — "setae cultratie." Anal cirri un- 

 changed, but anus, beside these, surrounded by a large number of short 

 cylindrical appendages. Color of specimen examined had nearly disappeared, 

 only black spots on feet were preserved. 



The form N.fucata ji inquiUna which lives symbiotically with Eupagurus 

 lernkardus corresponds with above except that the upper lobe of the para- 

 podium is enlarged to hold eggs, the sexual garb is lacking, and muscular 

 and cuticular layers, including pigment are feebly developed in posterior 

 region of the body. 



For an admirable diagnosis of this species, the reader is referred to Wiren's 

 description of which we have given only the above abstract. 

 Zoological Department. 



Columbia University, March 4, 1897. 



*For the benefit of any who may find trouble in reading the account in Swedish, I 

 give the following translation from Wiren's article, p. 8. 



" The feet of the unchanged part of Heteronereis glaucopis resemble not at all the 

 corresponding feet ofJV. fucata. The most characteristic quality of the latter is the 

 considerable size of the upper foot lobe compared with other parts of the foot. In 

 Heteronereis glaucopis, on the contrary, the upper lobe of the superior foot part i& 

 neither longer nor higher than the next below. Likewise does the latter named form 

 lack the dark spots on the ends of the foot part characteristic to N. fucata and even 

 seen in old alcoholic specimens. Of all known atocous forms it seems to me that 

 Nereis zonata is the one which resembles most Heteronereis glaucopis Malm. The 

 geographical distribution of the former speaks evidently against the alliance of the 

 two forms. But, perhaps, the individuals with sexual garb may be found far outside 

 the region of distribution of the normal species. 



"Epitocous forms ot iV./Mca^a have been found but once in Bohusliin where the col- 

 lector, C. Kolthoft, took a very well developed male swimming at the surface together 

 with epitocous N. longissima and N. diversicolor. * * * It corresponds in the arma- 

 ture of proboscis, head and appendages, completely with the atocous form, except that 

 the eyes, as is generally the case in mature Nereid individuals, are larger and furnished 

 with better lenses. However, they are not so large in this specimen as in most other 

 epitocous Nereis forms." 



