84 Papers from the Marine Biological Laboratory at Tortugas. 



tween Doliolum and Salpa, showing that the two are not closely related. 

 In relation to this opinion, I give two quotations from my memoir on " The 

 Genus Salpa " (Baltimore, 1893 : the Johns Hopkins Press). My purpose in 

 calling attention to the subject in 1893 was to show that there is no basis 

 for the opinion that the salpas and the doliolums are so different in the 

 character of their muscles that they can not be included in a single group 

 nor have had a common origin. Since the text-books still convey the im- 

 pression that the difference is fundamental and of great importance, it has 

 seemed best to call renewed attention to the subject. 



(Page 9.) This error has been most persistent, and it has been made the basis 

 of the fundamental classification of the whole Sal pa- family, for which Claus has 

 proposed the name Desmomyaria, and Herdman the name Hemimyaria, as distin- 

 guished from the Doliolidre, for which Gegenbaur has proposed the family name 

 Cyclomyaria. Even if this distinction between Salpa and Doliolum were absolute, the 

 selection of a characteristic so inconstant as the form of the locomotor muscles as 

 a basis for fundamental classification would be most unwise, and it is quite untenable 

 if it is not absolute. As a matter of fact, some of the muscle-bands of Doliolum are 

 incomplete, and in at least one species of Salpa some are complete. In the first gene- 

 ration or " amme " of Doliolum the seventh body-muscle is incomplete dorsally, and 

 in the animal that arises from a median bud the Pflegetheir it is incomplete ven- 

 trally, while the Ernahrungstheire, or products of the lateral buds, depart very widely 

 from the cyclomyarian type. So far as I am aware, Traustedt is the only modern 

 writer on Salpa who has used his eyes and described the muscle-bands as complete 

 circles, as they really are. In his description of this species (Spolia Atlantica. Bidrag 

 til Kundsscab von Salperne. Mem. Acad. Royal, Copenhagen, 6, 2, n, 8, Ger. by M. P. 

 A. Traustedt) and also in his description of the variety flagellifera, p. 369, he states 

 the facts correctly; but while his draughtsman, Cordts, has figured .S. democratica 

 correctly, plate n, figures 25 and 26, he has followed tradition in his figure of Salpa 

 flagellifera, plate i, figure 12, rather than nature and Traustedt, so hard it is to combat 

 established error. 



(Page 128.) I have already shown, p. 9, that the contrast in the muscle-bands 

 upon which the groups Cyclomyaria and Hemimyaria are based has no existence. In 

 all the doliolums some of the muscle-bands are imperfect rings ; in most species of 

 Salpa the oral and atrial muscles are perfect rings, and, in the most common and 

 best-known species of Salpa, the solitary S. democratica, most of the body-muscles 

 are as perfectly closed, dorsally and ventrally, as the rings of Doliolum. Anchinia, 

 at least, is only by courtesy a Cyclomyarian, for it has no circular muscles except 

 the oral and atrial sphincters, as the figure of the sexual animal given by Kowalevsky 

 and Barrios clearly shows. (Journ. Anat. Phys., xix, 1883.) The groups Cyclomy- 

 aria and Desmomyaria are then purely artificial and without scientific value. 



In the extracts that I have quoted from my memoir of 1893 ^ naf ^ no 

 thought of denying the well-known fact that the various species of Salpa 

 form a natural group and the doliolums and their allies another. The con- 

 text of the two passages that I have quoted shows that my purpose was to 

 show the error of the opinion that these two groups are widely separated 

 and belong in different phyla in the Tunicata, an opinion that is formulated 

 by Uljanin, in his memoir on Doliolum, in the statement that he regards 

 Salpa as standing alone among the tunicates, and that its resemblance to 



