30 PHYLUM TUNICATA (UROCHORDA). 



sand, rarely peduneulated, pharynx with 4 or less than 4 folds on 

 rach side, gonads in the form of a number of small separate masses 

 -i -altered over the inner surface of the mantle, calcareous spicules in 

 connective tissue of the mantle, most seas. 



Fain. 3. Molgulidae. Usually free, sometimes fixed, rarely 

 stalked : test usually covered with sand adherent to long, hair-like 

 processes of the test (Fig. 21) : mouth G-lobed, atrial aperture 4-lobed ; 

 dorsal tubercle extremely variable, being circular, slightly spiral, and 

 largely spiral within the limits of a single genus ; pharynx wall usually 

 longitudinally folded* (5-7 folds on each side), internal longitudinal 

 bars without papillae, stigmata more or less curved, usually arranged 

 in spirals (Fig. 22) : tentacles usually much branched, of two or three 

 regularly alternated sizes ; intestine attached to inner surface of 

 mantle on left side : renal organs aggregated in a sac upon the right 

 side : gonads on inner surface of mantle, usually paired (Fig. 22) ; 

 larvae anurous in a few species. 



Molgula Forbes (Fig. 19), apertures not laciniated, pharynx with 

 or 7 folds, most seas. Anurella L.-Duthiers, very similar, larvae 

 anurous. Gymnocystis Giard. Pera Stimpson, pharynx with 5 folds, 

 Atlantic and Arctic. Asro[>t ra Herd., stigmata not in spirals, lobes 

 of the apertures plain, abyssal, test without processes, stalked. Ker- 

 iHielen. Ctenicella L.-Duthiers, apertures laciniated. Aled. Eiigyra 

 Alder and Hancock, pharynx not folded, but with saccular divert i- 

 cula in longitudinal rows, gonads impaired, most seas. Paramolr/ula 

 Traustedt, pharynx without folds, stigmata spirally coiled and in in- 

 fundibula. gonads paired. Bostrichobrunrlnix Traustedt: (l(mni*l<r 

 Pizon. Olnintn inn Bourne. New Britain. 



Tribe '2. ASCIDIAE COMPOSITAI: (SVNASCIDIA) i 



/V.m/ (t .<<< />l Coelocormus) colonial forms, tin individuals of 

 n-li i<-li n /it-oil nci by gemmation and are embeddnl in common 

 test (except Claveli>ii</<i< ). 



The embryos usually undergo their development in the atrial 

 cavity <>r in a special incubatory pouch which they do not leave 

 until they have developed into the tailed larva. 



Vain. 1. Botryllidae. <'olon\ usuallv thin and encrusting, sometime- 

 in the form of thick flesh \ masses; zooids arranged in systems (Fig. 23) 

 circular or elliptical or in branching lines, the x.ooids of a >\stem openinu 



int 1 1 one CO! on cloaca ; C moil cloaca I openings (list ii let . usually lobed : 



/.odi<ls short, not divided into regions, disposed almost tangentially 1<> the 

 sui-face nf the colons- : intestine on the left side of the posterior part of 



'I' In folds arc really longitudinal rows of saccular project ions ( inhnnli - 

 i> nli i) of t lie phar\ ns_eul \\ all into t lie peril ira nchial ca\ il \ . 



i' I'i/.oii, Histoire dc la Uastonenese chc/. les Hotryllidcs. Ann. Sd. \n/. 

 (7). 14, 1SII3. /</.. Embryog6nie dc la larxe doiililc dcs Diplosomidc^. 

 ('nniftt. Hiinl.. iS'.tS. lil.. l-]t uilcs biologiijiics sur les 'runiciers ( 'oloniaux 

 fixes, Hull. Sue. <)<i,xt Friinrt', 10, l!MI(l. Hjort. I'cb. d. Ent v, ickelungs- 

 cyc'us del 1 zusammengesetzten Ascidicn, Xa/i/i-K Mil. 10, 1893. p. .">S4. 



