vol. 2, pt. 2.1 A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 



51 



Fig. 22.— Brooksia kosteata, solitary form, viewed from 

 the left side. from traustedt (1893). 



coimection with the intermediate muscle to move the protuberance, 

 much as the proboscis muscles in Brooksia must move the proboscis, 

 were it not that the test in the Salpae (sensu strictu) seems too firm to 

 allow much movement. 



It is difficult, from the published descriptions and figures, to deter- 

 mine the number of body muscles, partly because the details of the 

 oral region are not given 

 for the adult form, so as 

 to enable us to distin- 

 guish body muscles from 

 oral muscles, and partly 

 because there is disagree- 

 ment between Apstein's 

 figures of the embryo and 



Traustedt'sandlhle'sfig- >>fc>X el. 



ures of the adult. Trau- ^ — ?L- 



stedt and Ihle both show pi. 



what seems to be an in- 

 termediate muscle and 

 seven body muscles. All the body muscles are continuous across the 

 mid line dorsally and there is here, in some specimens, no union antero- 

 posteriorly between adjacent muscles. In other individuals, body 

 muscles I, II, and III are united dorsally, as are also muscles IV, V, 

 VI, and VII. The muscles of the proboscis are unique among the 

 Salpidae. Traustedt's and Apstein's descriptions of them do not 



quite agree. In Apstein's 

 figure of a side view of an 

 embryo the dorsal bundle of 

 muscles in the protuberance 

 is continuous with the second 

 sphincter of the lower lip. 

 The ventral bundle of pro- 

 boscis muscle fibers is pro- 

 longed on each side to nearly 

 the posterior end of the body. 

 It is doubtful if these bands 

 are comparable to the less 

 extensive ventral bands in the solitary Cyclosalpa virgula (pi. 11, 

 fig. 26). 



The oral muscles have been insufficiently described for use in 

 detailed comparison. Apstein figures the presence of an oral re- 

 tractor of the usual type and certain sphincters of the two lips. The 

 atrial muscles are not described beyond Traustedt's figuring the 

 presence of apparently very numerous delicate sphincters. 



Fig. 23. — Brooksia rostrata, embryo, viewed from 

 the right side, x 50 diameters. From Apstein 

 (1894, b). 



