216 TAGE SKOGSBERG 



Variabiliiy. Remarks: — As is seen from the description given above, this species is distinguished, 



contrary to most other forms of this sub-family that are dealt with in this treatise, by the 

 fact that several organs, especially the first antenna and the sixth and seventh limbs, are subject 

 to a not inconsiderable variation. In spite of this it seems to be very probable that we are 

 dealing with a single classificatory unit. In any case the striking continuity shown by the 

 variation, in spite of the limited material, supports this view. 

 Relationship. How is this forni related to C4. W. MOller's previously described Pacific species 



of this genus? 



G. W. Mi'LI.er's description of 6'. Agassizi (1895) is rather incomplete. In spite of 

 that I believe that one may say with pretty great certainty that the Atlantic form described 

 above by me is a new species, well differentiated from G. Agassizi, which was in reality 

 already to be assumed a priori on account of the fact that the two forms were caught in 

 two districts fairly well separated from a zoological point of view. 



The characters in which G. Agassizi is differentiated from the Atlantic species are 

 as follows: 



The length of the shell is greater (G. W. Muller, [1895] gives 23 mm., 1912 only 21 mm.). 



First antenna: This has only seven joints. ,,Das letzte Glied, an dem sich Reste 



einer Verschmelzung aus 7 und 8 nicht nachweisen lassen . . . ." In the male the five 



proximal filaments on the b-bristle and the two proximal filaments on the c-bristle are 



modified for seizing the female. 



Second antenna: The exopodite has no basal spines on the third to the ninth 



joints; the second joint on the female endopodite has no bristles; the bristle of the end 



joint of the last-mentioned branch does not attain the length of the endopodite. 



The seventh limb has more than 200 cleaning bristles on each side. 



In all these characters the Atlantic form seems to be more primitive than the Pacific 



form. — To judge from G. W. Muller's drawings the two forms seem to be differentiated 



in still more characters. The superficiality of the drawings makes it rather probable, however, 



that these differences are due, at least in part, to lack of exactitude on the part of the author; 



on account of this I have thought it best not to discuss these characters at any length here. 



Synonymy. In a later work (1906 b) G. W. MULLER mentions (p. 135) that about ten, mostly 



young, specimens of this genus — ,,Alle gehoren, soweit ich das feststellen konnte, zu 



Gigantoci/pris Agassizii'^ — were caught by S/S ,,V a 1 d i v i a"* between lat. 14" N. and 



lat. 42° S. in the Atlantic and Indian Oceans. Only two pictures of habitus were given. 



Whether any of these finds are to be referred to my above described species it is impossible to 



decide. It may, however, be pointed out that fig. 5, pi. V shows a type of shell so different 



from the one that is characteristic of my species that an assumption of this sort seems anything 



but probable. — It may be stated in passing that this figure also suggests most decidedly that 



G. W. muller's identification with G. Agassizi is incorrect. 



It is true that the material of the ,,V a 1 d i v i a" expedition was subjected later on 

 to a renewed investigation by L. LUDERS (1909), but this author's drawings of the limbs, etc. 

 * See also C, Chun, I'JOu, p. 515. 



