DORIDID^. 369 



The only Xudibranch with a solid upper jaw, is JEgirus 

 punctilucena. In other instances the two halves are articulated 

 and act as lateral jaws. In ^girus the mouth is also furnished 

 with membranous fringes. Ancula cristata has a formidable 

 spinous collar. The skin acts as an accessory breathing-organ ; 

 it performs the function entirely in the Elysiadse, and in the other 

 families, when by accident the branchiis are destroyed. The 

 water on the gills is renewed by ciliary' action. The fry is pro- 

 vided with a transparent, nautiloid shell, closed b^^ an oper- 

 culum, and swims with a lobed head-veil fringed with cilia, like 

 the young of most other gastropods. 



" While the numerous tribes of Mollusks fui'nished with testa- 

 ceous coverings offer us objects of contemplation remarkable 

 alike for their extreme beaut^^ and the durability of their calca- 

 reous envelopes, the scarcely less extensive and certainly far 

 less known families of naked-gilled gastropods exhibit an aston- 

 ishing variety of form, extreme delicacy of organization, and 

 great diversity of color to captivate the eye and occupy the 

 attention of those who wander by the shore or explore the 

 depths of the ocean. Clinging to the stems of floating sea- 

 weeds, many, like the Anthobranchs, will be seen extruding 

 their flower-like gills of surpassing elegance, exploring with their 

 foliated tentacles or complex mantle-filaments the plants around 

 them, the brilliant hues of their striped or spotted bodies 

 glancing through the water ; some will be observed with bodies 

 so fragile and pellucid that yon may see the color of their blood 

 and count the pulsations of their hearts ; some will be seen to 

 have their gills disposed in rows of papillary tubercles on the 

 sides of their bodies, like the Solids, or tree-like and branching, 

 like the Tritonias ; the foreheads of some will be smooth and 

 simple, while those of others will be found adorned with various 

 singular appendages ; in others, again, all processes will disap- 

 pear, all branchial arrangements vanish, and we shall meet with 

 forms almost as simple in their appearance as the Nemertoid 

 types among the Annelids." — H. and A. Adams. 



Suborder ANTHOBRANGHIATA. 



The branchiae more or less surrounding the anus upon the 

 medio-dorsal line. 



Family DORIDID^. 



Mantle (nothseum) large, without marginal appendages ; skin 

 generally very spiculose ; dorsal tentacles (rhinophora j laminate 

 and retractile within cavities. Dentition (xiii, 69). 



Doris, Linn. 

 Syn. — Argus, Bohadsch. Archidoris, Bergh. 

 Distr. — 157 sp. Universal. D. Johnsioni, Alder and Hancock 



(xc, 92). 



