vol. 2, pt. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 33 



ventrally, fusing into a common mass. The dorsal ends of the 

 body muscles converge more than in the other Cyclosalpae symmet- 

 ricales. The intermediate muscle is continuous ventrally but 

 interrupted dorsally. 



At first glance the oral muscles seem to show a pattern similar to 

 that of Cyclosalpa pinnata, but closer observation shows the details 

 of their relations to be quite different. The figure needs some 

 description. The dorsal retractor is seen to divide into four bands, 

 the lower or fourth of which passes forward into the lower lip to form 

 what at first glance seems to be the first sphincter of the lip, but it 

 is really the third sphincter. The lower lip is very strongly inturned, 

 so that its first and second sphincter muscles appear in side view to 

 lie behind the third sphincter. The upper branch of the dorsal 

 retractor forms the first or admarginal sphincter of the strongly- 

 incurled lower lip. The second branch of the retractor forms the 

 second sphincter of the lower lip. The third branch of the retractor 

 passes up outside the first and second branches to form the second 

 sphincter of the upper lip. The first sphincter of the upper lip 

 arises by one or two branches on each side from the second sphincter 

 of the lower lip. (Compare with solitary and chain forms of Cyclo- 

 salpa bakeri.) The third and fourth sphincters of the upper lip 

 unite below into the ventral retractor which, as in 0. pinnata, passes 

 inside the dorsal oral retractor and outside the intermediate muscle, 

 diagonally downward and backward, to unite with the first body 

 muscle, near its ventral end. The dorsal connection of the fourth 

 sphincter of the upper lip with the intermediate muscle is as in 

 Cyclosalpa pinnata, though the former is more prolonged postero- 

 dorsally. Note that the third sphincter muscle of the lower lip in the 

 solitary C. jloridana is a branch of the dorsal oral retractor, as in 

 the aggregated C. pinnata, C. baJceri, and C. virgula, while in the 

 solitary C. pinnata and C. bakeri it is a branch of the ventral oral 

 retractor. 



The muscles of the atrial siphon differ slightly from those of either 

 Cyclosalpa pinnata or C affinis. There are fewer, but three, delicate 

 sphincters, all of which are unbranched. There are two stronger 

 basal sphincters, also unbranched, and there is a well-developed 

 diagonal atrial retractor which continues ventrally as far forward 

 as the last body muscle. 



The gut (see also fig. 14) shows the usual trumpet-shaped eso- 

 phageal opening and an excessively curved esophagus which opens 

 into a small right caecum near its origin from the intestine. The 

 straight intestine lies, as in the solitary forms of all the Cyclosalpas, 

 along the dorsal side of the gill. The left caecum is noticeably larger 

 than the right and lies further from the mid line. 



