IOO TUNICATA SALPIANS CHAP. 



vertical distribution of these Thaliacea in the sea than any other 

 factor. 



Other Genera. Anchinia, of which only one species is 

 known, A. rubra, Yogt, from the Mediterranean, has the 

 sexual forms permanently attached to portions of the dorsal 

 outgrowth from the body of the unknown oozooid (" nurse "). 

 The stolon is probably much longer than in Doliolum, and curves 

 round so as to reach and lie along the dorsal outgrowth, upon 

 which it places the buds. 



The body of the adult is elongated dorso-ventrally. The 

 test is well developed and contains branched cells. The mus- 

 culature is not so well developed as in Doliolum. There are 

 two circular bands at the anterior end, two at the posterior, and 

 two muscles on the middle of the body, which unite to form the 

 characteristic S-shaped lateral bands. The stigmata are confined 

 to the obliquely-placed posterior end of the branchial sac. The 

 alimentary canal forms a U-shaped curve. The reproductive 

 organs are placed on the right side of the body. The life-history 

 is still imperfectly known. As in the case of Doliolum the 

 sexual generation is polymorphic, and has three forms, two 

 of which remain in a rudimentary condition so far as the 

 reproductive organs are concerned. They are known as the 

 first and second sterile forms, or " trophozooids." In Anchinia, 

 however, the three forms do not occur, so far as we know, 

 together at the same time on the one outgrowth, but are 

 produced successively, or in different regions, the reproduc- 

 tive forms of the sexual generation being independent of the 

 " foster-forms." l 



The third genus, Dolchinia, contains also only a single species, 

 D. mirabilis, found by Korotneff 2 in the Gulf of Naples. It 

 must have three different forms in its life-history oozooid, 

 phorozooid, and gonozooid, but the first of these is still unknown. 

 On what must be body processes detached from the oozooid 

 are found phorozooids somewhat like those of Doliolum, bearing 

 sexual forms attached to ventral stalks. Dolchinia is inter- 

 mediate on the whole between Anchinia, the most simple member 

 of the family, and Doliolum the most complex ; and may eventu- 

 ally come to be united with the latter genus. 



1 See Barrois, Journ. d'Anat. et Physiol. 1885. 

 2 Mitth. Z. Stat. Neapel, x. 1891. 



