344 MOLLUSCA. 



ganization observed in Doris and Tritonia, but their branchiae, 

 instead of being placed on the back, resemble two long series 

 of laminae, situated on the two sides of the body, under the 

 projecting margin of the mantle. 



Phyllidia, Cuv. 



The mantle naked, usually coriaceous, and without any shell; the 

 mouth, a small proboscis, each side of which is furnished with a 

 tentaculum; two others project from above two small cavities in the 

 mantle. The anus is on the hind part of the mantle, and the genital 

 orifices forward, under the right side; the heart near the middle of 

 the back; the stomach simple and membranous, and the intestine 

 short. 



Several species inhabit the Indian Ocean(l). 



DiPHYLLIDIA, CuV. 



The branchiae similar to those of the Phyllidise, but the posterior 

 part of the mantle more pointed; on each side of the semicircular 

 head a pointed tentaculum and a slight tubercle; the anus on the 

 right side(2). 



ORDER IV. 



TECTIBRANCHIATA(3}. 



The branchise along the right side or on the back, composed 

 of laminae more or less divided, but not symmetrical ; they are 



(1) Phyllidia trilineata, Seb., Ill, i, 16; Cuv., Ann. du Mus., V, xviii, 1; and 

 Zool., Voy. Freycln., pi. 87, f. 7 10; Ph. ocellata, Cuv., lb. 7; PA. pustulosa,. 

 Id. lb. 8, and some new species. 



(2) Diphyllidia Brugmansii, Cny . ,Diphyll. lineata, Otto., Nov. Act. Nat. 

 Cm., X, yii, or Pleuro-phyllidia, Meckel., Germ. Archiv., VIII, p. 190,pl. ii,. 

 delle Chiaie, Mem., X, 12. 



N.B. The Linguelle of Elfort, Blalnv., Malac, pi. xlvii, f. 2, does not appear to 

 differ from our first species. 



(3) M. de Blainville has given to this order the name of Monopi.euiiobrak^ 



CniATA. 



