34 CALIFORNIA ACADEMY OF SCIENCES. 



Deltania Benhami. In tlie genital region, the distance between the two inner setfe 

 diminishes toward the male pore, almost in the same way as in Deltania elegans, with, 

 however, a slight but characteristic difference. The inner or first seta in xviii is 

 often, 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 setse in xix and xx are closer together than normally, but 

 already in xxi the setiie have regained their proper distance. Again, anterior to the 

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

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

 Deltania elegants, we find that the arrangement relatively in front and behind the 

 male pore is reversed. While in Deltania elegan>i, the anterior seta? quickly con- 

 verge, the posterior ones approach slowly. In Deltania Troi/eri, the opposite is the 

 case. 



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

 with the arrangement of the setie in Deltania Benhami, we find that in the present 

 species the setfe in the ventral couples, as well as those couples themselves, are 

 much further apart than in Deltania Benhami. The deltoid arrangement, also, is 

 different in the two species, of which the figures give a better idea than an}' lengthy 

 description (figs. 24, 39, 40). ^ 



The srtcs of 2')cnial setce (fig. oo) are found as usual in the vicinity of the male 

 pore in xvii. There 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 developed seta. In 

 Deltania ekyana there are three or four set* in each sac. 



Alimentary canal (figs. 2G and 27). The buccal cavity extends superiorly to 

 ii, inferiorl}' to v. The pharynx ends in v, and is much less tleveloped than in 

 Deltania elegans. The upper fold is, however, very large. There are one pair of 

 long and narrow salivary glands in each of iii and iv, and one pair very large com- 

 pact ones in iv. The oesophagus commences in v, and rises to a sigmoid plexus in 

 viii. It is greatly contracted at the septa. In xv and xvi it narrows down to a tubu- 

 lar intestine. 



The sacculated intestine commences in xvii, but attains its full widtli first in 

 xix or XX. There is no gizzard, no calciferous glands nor pouches of any kind at- 

 tached to the alimentary canal. 



Nervous Stjstem (fig. 28). The characteristic feature of the nervous system is 

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

 with almost imperceptible contractions at the septa. In Deltania elegans this contrac- 

 tion is very prominent, and the ganglion is almost twice as wide in the jjosterior jiart 

 of the segment as in the anterior one. This characteristic appears constant. In 

 Deltania Benhami the ganglion is narrowed somewhat at the septa, but the posterior 

 part in each segment is not any wider than the anterior part. 



