108 



TUNICATA. 



Order 1. DESMOMYARIA (SALPJE). 



Thaliacea of cylindrical, usually dorso-ventrally flattened form, with 

 band-shaped muscular hoops and thick mantle (fig. 566). The 



FIG. 568. The forms of Doliolum. denticulatum (a, b, d, e, after C. Grobben ; c, after Gegenbaur). 

 a, Sexual animal. 0, Mouth ; A, cloacal aperture ; Kl, cloacal space ; N t nerve centre ; 

 Us, cxitaneous sense organ ; Wb, arch of cilia ; Wg, ciliated pit ; End, endostyle ; Br, gills ; 

 (7, heart ; D, intestine ; T, testis ; Ov, ovary ; M , muscular hoops. 6, First asexual 

 generation. Stv, Ventral stolon ; Std, dorsal stolon ; Ot, auditory organ, c, A later stage 

 of 6, with developed dorsal stolon and aborted intestine and gills, less highly magnified. 

 Ms, Median buds ; Ls, lateral buds, d, Nutritive animal produced from the lateral buds 

 with large mouth and without cloaca ; Oe, oesophagus, e, Doliolum larva with larval tail ; 

 Ch, chorda (urochord). 



anterior opening is furnished with a valve-like lip which can be shut 

 down. The gill reaches from the ganglion to the oral region, and in 

 consequence of the development of two large lateral branchial slits 



