LAGANUM DIPLOPORUM. 49 



difference between the two species in form; comparison of fig. 9, PI. 127, with 

 fig. 7 of the same plate will reveal the difference in tuberculation; and com- 

 parison of figs. 10-12, PI. 127, with fig. 8 of the same plate, shows at once the 

 curious difference in genital pores. As regards this latter character it will be 

 noted that there is great individual diversity in the position of the posterior 

 pair of pores with relation to each other. In typical cases, they are well sepa- 

 rated (PI. 127, fig. 12), but they are often near together (fig. 11) or even more or 

 less merged (fig. 10), and when they are merged into one it is often difficult, and 

 may be impossible, to see that there are two. (Of course, it is not probable 

 that two pores are ever merged; the probability is that in such apparent cases 

 we have incompletely separated pores arising from a single one; i. e. the single 

 pore is the primitive, the pair of pores, the derived condition). When the two 

 pores are quite distinct, each has its own genital duct, several millimeters in 

 length, but it is not easy to decide whether there are two distinct gonads; the 

 appearance is more that of a single, much branched gonad with two separate 

 ducts. The spines and pedicellariae of diploporum are not certainly distinguish- 

 able from those of fudsiyama. In coloration too, the two species are not unlike. 

 The largest specimen of diploporum in the Albatross collection is 50 mm. long. 

 Specimens under 15 mm. are not certainly distinguishable from fudsiyama and 

 most specimens under 20 mm. do not show six genital pores. All of the speci- 

 mens are from Japan and were taken at the following places. Many are nearly 

 or quite bare. 



It is notable that fudsiyama was taken at only one of these stations. 



Station 3707. Off Ose Zaki, Honshu, Japan. Bott. temp. ? 63-75 fms. 

 Vol. s., a., g. 



Station 3748. Off Suno Saki, Honshu, Japan. Bott. temp. ? 73-200 

 fms. Yl. s., rot. co. 



Station 4885. Between Nagasaki and Kagoshima, Japan. Bott. temp. 

 62°. 53 fms. Dk. gy. s., brk. sh. 



Station 4888. Between Nagasaki and Kagoshima, Japan. Bott. temp. 

 59.7°. 71 fms. Dk. gy. s., brk. sh. 



Station 4893. Southwest of Goto Islands, Japan. Bott. temp. 55.9°. 

 95-106 fms. Gy. s., brk. sh., p. 



Station 4895. Southwest of Goto Islands, Japan. Bott. temp. ? 95 fms. 

 Gn. s., brk. sh., p. 



Station 4902. Southwest of Goto Islands, Japan. Bott. temp. 52.9°. 

 139 fms. Gy. s., brk. sh. 



