Mr. J. D. Macdonald on a new form of Compound Tunicata. 405 



intestine drawn upwards, taking with it the stomach and ova- 

 rium. In short, it will have acquired the characters of Bol- 

 tenia (C). 



Still further, let the point of suspension be 1, C, and the ver- 

 tical axis of the body will assume greater obliquity. The endo- 

 style will be bent upon itself («, D), thus altering the direction 

 of the branchial bars ; the mouth, stomach, and intestinal loop 

 will be still more elevated, and the anal aperture more depressed, 

 so that the resulting animal will correspond with one of the 

 zooids of our new genus (D). 



The points of diflference between the latter and Boltenia are 

 given in the following columns : — 



Chondrostachys. 



Tentacula simple. 



Mouth nearly opposite the 

 branchial orifice, widely sepa- 

 rated from the vent. 



CEsophagus long. 



Stomach subglobose, straight, 

 and corresponding with the 

 long axis of the body. 



Flexure of intestine dextral. 



Rectum anterior. 



Length of alimentary canal 

 from the mouth to the flexure 

 one-half less than from the 

 flexure to the vent. 



No true liver. 



No pallio-vascular canals in 

 the test of the body. 



Boltenia. 



Tentacula compound. 



Mouth near, and rather in- 

 ferior to the vent, and both ap- 

 proximating the cloacal open- 

 ing. 



(Esophagus short. 



Stomach full, elongated, 

 curved, and nearly parallel with 

 the short axis of the body. 



Intestinal flexure antero- 

 posterior. 



Rectum lateral. 



Length of alimentary canal 

 from the mouth to the flexure 

 rather more than from the 

 flexure to the vent. 



A well-organized system of 

 hepatic glands. 



Minutely ramified and reti- 

 culated pallio-vascular canals 

 in the test of both body and 

 stem. 



Both right and left ovaria 

 present. 



Only the right ovarium, or 

 that included in the intestinal 

 loop, present. 



Whoever looks for a veritable affinity here, will certainly be 

 disappointed, though it must be conceded that the general 

 resemblance is quite as close as one might expect the zooids of 

 a representative compound form could bear to such a remarkable 

 though simple Ascidian as Boltenia^. 



* [We venture to think that the true position of Chondrostachys is be- 



