MALACOZOA. GASTEROPODA. CIRROBRANCHIATA. 71 



branchial tufts. Named, I suppose, from its plain or 

 ignoble aspect. 



Cyclobranchiata. 

 Branchice in a circle behind. 



Family TIL — Dorina. 



Body oval or elliptical, convex above, with the bran- 

 chial tufts arranged circularly on the upper part of the 

 body behind ; four tentacula. Named from the Genus 

 Doris. 



Genus 1. Doris. — Body oval or elliptical, more or less 

 convex and tuberculate above ; the branchiae in a circle 

 behind ; the mouth a short fleshy tube, ■with a denticu- 

 late lingual mass. Doris, "the mother of the Nereids." 



1. Doris tuberculdta. — Ovato-elliptical, convex above, 

 grey, covered above with small unequal depressed, gra- 

 nulated papillae ; the margin of the mantle thick and 

 considerably expanded. Tuberculdtus, covered with 

 tubercles. 



2. Ddris obveldta. — Oval, depressed, pale yellowish, 

 covered above with numerous unequal, much depressed, 

 granulated tubercles ; the margin of the mantle thin, re- 

 pand, projecting far beyond the foot ; upper tentacula 

 rugoso-granulate. Verrnc6sus, warty. 



3. Ddris bilamelldta. — Oval, depressed, covered 

 above with small, unequal, round tubercles, longer and 

 more crowded toward the margin ; the edge of the 

 mantle thin, considerably extended ; upper tentacula 

 with the margin of their sheath bituberculate. Bilamel- 

 latus, with two plates. 



4. Doris dspera. — Ovato-elliptical, very convex above, 

 covered with rather large, nearly equal, round tubercles, 

 the margin of the mantle not extending far beyond the 

 foot ; upper tentacula rugoso-granulate. Asper, rough. 



ORDER IX.— GASTEROPODA CIRROBRANCHIATA. 



Respiratory apparatus of tufts of tentacular filaments 

 on the sides of the neck. 



