The Pelagic Tunicata of the Gulf Stream. 85 



Doliohini is superficial and due to secondary adaptation, an opinion which 

 seems to be shared by most of the writers of text-books. 



THE MUSCLES OF THE SOLITARY CYCLOSALPA. 



The homology between the muscles of the various species of Cyclosalpa 

 becomes very conspicuous as soon as careful and accurate drawings are com- 

 pared, for it is very exact and complete, and the equivalent of each muscle 

 in any one species can be identified without difficulty in all the others. For 

 this purpose more careful drawings of the muscles and a more minute sys- 

 tem of designating them than are found in most of the descriptive literature 

 are necessary. 



I give, in text-figure i, a ventral view of the adult solitary 5\ pinnata, 

 and, in plate x, figure 13, a side view of the embryo of the same, with the 

 system of lettering that is used for S. floridana in plate I, figures I and 2. 

 The muscles 6, 7, 8, 9, 10, and 1 1 are incomplete, both dorsally and ventrally, 

 and they are independent and not united into groups, as they are in S. flori- 

 dana,, but, in other respects, the description of the muscles of S. floridana 

 on pp. 76-78 applies to S. pinnata, as it does also to 5". affinis, and, probably, 

 to S. virgula, although I have not had an opportunity to study this species, 

 and know of no good figure of the solitary form. 



The muscles of v$\ floridana are shown in dorsal view in plate I, figure 

 i, in ventral view in figure 2, and side view in figure 7. In all of the 

 figures the muscles that are on the near side are designated by Arabic numer- 

 als, and those on the far side, that are seen through the transparent body, 

 are designated by Roman numerals. 



Muscle i crosses the middle line of the dorsal surface of the body, just 

 posterior to the slender oral muscles, and, bending around on to the ventral 

 surface, runs backwards, and, uniting with muscle 5, forms muscle 6. 



Muscle 2 is a dorsal longitudinal muscle, which connects muscle i with 

 muscle 4. 



Muscle 3 crosses the middle line of the ventral surface posterior to the 

 anterior end of the endostyle and the ciliated band, and, bending around 

 on to the dorsal surface, unites with muscle 2 to form muscle 4. 



Muscle 4 is a dorsal longitudinal muscle that is formed by the union of 

 muscle 2 and muscle 3. 



Muscle 5, arising near the middle line of the dorsal surface, runs out- 

 wards and forwards, and, bending on to the ventral surface, and running 

 inwards and backwards, unites with muscle i to form muscle 6. 



Muscle 6 is a ventral muscle that is formed by the union of muscle i 

 with muscle 5. 



Muscle 7 is nearly transverse dorsally, while its ventral half runs inwards 

 and backwards. 



Muscle 8 is transverse, both dorsally and ventrally. 



