34 CAMKOKNI A AnADEMY OF SriKMf'ES. 



Ddtanin Benhnmi. In llic <>;eiiitjil region, the distiincc between tlic two inner seta? 

 (liniinislies toward tlio male j)ore, almost in tiie same way as in Ddtanin elec/au^, with, 

 liowcver, a slight hut charaeteristic (lifTcicnce. Tlie inner or first seta in xviii is 

 ((tleii, but not always, wanting, probably falling out when young, before its full devel- 

 opment, as more frequently a rudimentary seta is seen in place of a fully developed 

 one. 



The first and second seta' in xix and xx are closer together than normally, but 

 already in xxi the setse have regained their |)roper distance. Again, anterior to the 

 male pore, the setse 1 and 2 in xi to xvi are closer than normally, those in xiv to xvi 

 are equidistant, while those in x to xiv lapidly approach. If we thus compare with 

 Di'lfdnia eler/iiiis, we lind that I lie an'angement relatively in front and behind the 

 male pore is reversed. While in J)i'lt<ini(i i'Jr(/nit!<, the anterior setic (piickly eon- 

 verge, the posterior ones ajiproach slowly. In Di'ltunhi 'I'lOijiTi, the opposite is the 

 case. 



The shape of the setse in the two species is very similar. Compared again 

 with the arrangement of the setas in Tk'ltanin Benhnmi, we find that in the present 

 species the seta' in tlie ventral couples, as well as those cou]>les themselves, are 

 much further apart than in Dcltunid BcnJianii. The deltoid arrangement, also, is 

 ilillcrenl in liie two species, of which the figures give a better idea than any lengthy 

 descrii)tion (figs. 24, 39, 40). 



Tile !«icf< (if jicnhtl x('ti( (fig. ;>.'>) are found as usual in the vicinity of the male 

 pore in xvii. Tiiere are seldom more than one seta in each sac. This seta is long, 

 slender, almost straight, occupying the whole length of the sac. Now and then there 

 is a rudimentary seta in the same sac, but never more than one devidoped seta. In 

 De/liniia r./ct/anx there are three or four setic in each sac. 



Alunt'iitdi// ciiiHil (figs. 2G and 27). The Imeeal cavity extends superiorly to 

 ii, interiorly to v. Tiie phaiynx ends in v, and is much less ilevelopeil than in 

 Dplhinin ekf/nni<. The upper fold is, however, very large. There are one pair of 

 long and narrow snlivary glands in each of iii mid iv, and one paii' vei'v large com- 

 pact ones in iv. Tile u'soplingiis eonimences in v, and I'ises to a sigmoid plexus in 

 viii. It is greatly contracted at the sepia. In \v and xvi it narrows down to a tubu- 

 lai' intestine. 



The saccnlatcil inlcslinc commences in xvii, imt attains its full widlli (irst in 

 xix or XX. Theri' is no gizzard, no calciferous glands nor pom-lie^ of any kind at- 

 tached to the alinieiilary canal. 



NervoiiH Sijs/cvi (fig. 2(S). The characteristic feature of the nervous svstem is 

 the even width of the ventral ganglion, the two sides being nearly parallel throughout, 

 with almost iniperc(q)tible contiiictions at the septa. In J)c/t(ini(t c/ii/aits this contrac- 

 tion is very prominent, and the ganglion is almost twice as wide in the posterior part 

 of tlu! segment as in the aiileiior one. This chaiacteiislic appears constant. In 

 /)('/li>iii(i /Icn/idnii the ganglion is narroweil sonu'what at the septa, but the posterior 

 part in each segment is not any wider llian the aiitcrim- part. 



