CLASSIFICATION OF THE TUNICATA. 645 



Dorsal lamina in tlie form of a vasculai' ciliated baud feversiag 

 the central cavity obliquely. 



Alimentary canal usually forming a small coiled mass placed 

 posteriorly and ventrally. 



Gonads hermaphrodite, but ova and spermatozoa not mature 

 together. 



Reproduction also takes place by gemmation, and alternation 

 of generations occurs in the life-history. 



The embryo develops in an incubatory pouch. No tailed larva 

 is formed. 



This family includes two very distinct groups of species usually 

 recognized as the genera 8alpa and Cyclosalpa ; but Lahille has 

 recently broken the former up into four sections or subgenera, 

 and I believe it will be convenient to follow that course. 



r Alimentary canal extended, no " nucleus," " chains " circular. 



\ Cyclosalpa. 



[ Alimentary canal coiled to form a " nucleus," "chains " ribbou-like ... 1 

 1 f Several embryos formed at a time lasis. 



I One embryo only at a time 2 



cf The embryo covered Salpa. 



"" \ The embryo exposed 3 



g f The dorsal lamina or " gill" having only ciliated bands Thalia. 



I The "gill" having rudimentary stigmata Pegea. 



Ctclosalpa, Blainville, 1827. 



Alimentary canal running antero-posteriorly, and not coiled 

 up to form a " nucleus." 



Gemmation results in the formation of a chain o£ aggregated 

 forms attached together in a circle. 



In other particulars like Salpa. 



This genus contains the following three species: — 



r With linear pigmented bauds on dorsal edge. 



\ C.2}innata, Fovsk. (Atl.,Pac.,Med.) 



[ With no such bands 1 



{Aggregated form has atrial aperture terminal, posterior. Solitary form 

 with no longitudinal muscles C. affinis, Cham. (Atl., Pac, Med.) 

 Aggregated form has atrial aperture dorsal. Solitary form with four 

 longitudinal muscles C. doUchosoma-virgula, Tod.-Vogt. 



[(Med.) 



Salpa, ForsTcul, 1775. 



Body not attached, elongated, with the apertures at the oppo- 

 site ends. 



Test gelatinous or cartilaginous ; trausparen^. 



Mantle with muscle-bands which are more or less incomplete 

 ventrally. 



