Miscellaneous. 197 



The genus Hero, established by Loven in 1839 for some small 

 moUusks collected in the seas of the north of Europe, has hitherto 

 been placed, by all naturalists (Alder and Hancock, G. 0. Sars, Bergh, 

 Fischer, &c.) who have paid any attention to it, in the family Den- 

 drouotidae, one of the subdivisions of the great group of the Tri- 

 toniadse. All these different naturalists seem to have had at their 

 disposal only individuals preserved in alcohol ; the figures given by 

 Bergh and Sars would lead to the belief that the appendages with 

 which the whole extent of the margin of the mantle is furnished are 

 dendritic in form. We believe that this appearance is the effect of 

 preservation in alcohol. 



The study of the jaws and radula ought to have shown that the 

 genus had nothing to do with the Dendronotidse. 



On observing living individuals, we at once see, from the con- 

 formation of their lateral appendages, that the genus Hero belongs 

 to the great group of the ^olididse ; in fact, these appendages, 

 which, in individuals preserved in alcohol, have a dendriform ap- 

 pearance, are really true fusiform dorsal cirri, arranged symmetri- 

 cally in pedunculated groups upon the lateral parts of the back. 

 These groups of cirri have much analogy with those of Cahira Cavo- 

 linii ; only in the genus Hero we find in front of the body, on the 

 sides of the cephalic region between the labial tentacles and the 

 rhinophores or dorsal tentacles, a pair of tufts of cirri which are 

 entirely deficient in the genus Calura. These two tufts possess the 

 longest and most numerous cirri ; aU. the groups posterior to the 

 rhinophores each present only one, two, or three rudimentary 

 cirri. 



From our investigations, the following generic diagnosis may be 

 drawn : — 



General form of the body resembling that of the Tritoniadffi, 

 with its dorsal margins distinctly keeled ; foot a little wider than 

 the body. 



Labial tentacles strong and recurved ; rhinophores simple and 

 non-retractile. Dorsal cirri fusiform, inserted dichotomously upon 

 short peduncles arranged on the lateral parts of the back ; the 

 peduncles of the first pair, placed in front of the rhinophores, are 

 the only ones forming groups well-furnished with cirri ; all the 

 post-rhinophorian peduncles bearing only one, two, or three rudi- 

 mentary cirri. Cnidophorous sac with numerous ncmatocysts. 



Anus in the middle of the right flank ; sexual orifice on the same 

 side, but placed further forward. Penis unarmed. 



Jaws with irregular denticulations on the masticatory margin. 

 Radula triseriate ; median tooth, with the plate denticulated. 



ffisophagean ring composed of four ganglia (two cerebroid and two 

 pedal ganglia) ; eyes pedunculate ; otocysts with numerous otoliths. 



The individuals taken in the Bay of Marseilles differ in several 

 characters derived from the radula and jaws from the Hero formosa 

 studied by Sars and Bergh. We regard them as representing a new 

 species. — Comptes liendus, July 9, 1888, pp. 136-138. 



