OXYNOEID^:. 161 



The genus SYMPTERUS Rafinesque, Analyse de la Nature, ou 

 Tabl. de 1'Univers et des Corps Organises, 1815, p. 142, is placed by 

 Rafinesque between Laplysia and Dolabella. It is an absolutely 

 nude name. 



Genus NOTARCHUS (page 135). 



APLYSIA SALTATOR Forbes. A. corpore globoso, griseo albo 

 nigroque maculato, tuberculato, tuberculis mucronatis ; sinu branch- 

 ali parvo ; pede augustissimo, tentacules brevibus. 



Long. 2 unc. ; Altitude 1 T V Hab. 20-30 fms. Serpho Bay 

 [JEgean Sea]. (Forbes, in Rep. Brit. Asso. Adv. Sci., 1843, p. 187). 



Family OXYNOEIDJE Fischer. 



Animal elongated, narrow, with rolled tentacles and well-de- 

 veloped pleuropodial lobes. Male orifice near the right tentacle ; 

 female orifice on the right side at the edge of the mantle cavity ; no 

 external groove between the orifices, the vas deferens being internal. 

 Gill composed of numerous delicate parallel leaflets, depending from 

 the roof of mantle-cavity, not forming a free plume. Radula com- 

 posed of a single series of lance-like teeth. Shell Bulliform, ex- 

 ternal, involute with concealed spire, thin and fragile, oval, incap- 

 able of containing the soft parts. 



The genera composing this group were referred by Pagenstecher 

 in 1874 to a new Order which he called Monostichoglossata, includ- 

 cluding Limapontia, Elysia, Lophocercus and Lobiger ; the group 

 being based mainly on the peculiar radula. Later, Bergh (Malak. 

 Untersuch.) forms a group Ascoglossa; and von Ihering, in 1877 

 (Vergleich. Anat. Nervensyst, p. 196), names the Order Sacoglossa, 

 including Litnapontiidce, Elysiidce, Phyllobranchidce, Piacobranch- 

 idw, Hermceidce and Lophocercidce. Mazzarelli, in 1892 (Bull. Soc. 

 Nat. Napoli, p. 98, and Mem. Soc. Ital. Sci. (3), ix, p. 1), in- 

 vestigated the anatomy of Lobiger, finding the nephridia as in many 

 Nudibranchs, nervous system as in Ascoglossa ; generative organs 

 fundamentally Ascoglossan, but the ovary and testis are separated. 

 He concludes that the Oxynoeidce represent the most primitive 

 Ascoglossa, derived phylogenetically from the more primitive Tecti- 

 branchs (Bulloidea) near the point of origin of the Pleurobranchs. 



On the other hand, Oxynoeidce differ from the Ascoglossa in hav- 

 ing a well-developed shell in the adult, a true gill (although differ- 

 ing much from the normal Tectibranch gill), and in the compact 

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