230 Prof. M‘Intosh’s Notes from the 
JT. atlantica has also a tendency to a dorsal curve (2.¢. a 
convexity towards the dorsal edge) throughout. It is the 
same type of bristle in both, but that from the abyssal 
species has been modified. The type of bristle is that of 
Dathousia atlantica of the ‘ Challenger ’*. 
The ventral cirrus is of considerable length, slender, subulate, 
and tapering. It extendsa little beyond the fleshy part of the 
foot. 
Clapaiéde in his species found the male elements developing 
in winter. 
The genus Tyrrhena was established by Claparéde + for a 
species first discriminated under thename of Costalia Claparédit 
in the manuscript of the fourth ‘Annuaire du Musée 
Zoologique de Naples,’ by Achille Costa. He characterized 
the genus (named after the sea it inhabited) as having few 
segments; the head-lobe provided with five antenna (two 
palpi and three tentacles); dorsal division of the foot with 
capillary bristles, ventral with compound bristles; 8 tentacular 
cirri; and the proboscis with two maxille. 
What relationship Claparéde’s or the present species has 
to the various forms described or alluded to by De 
Quatrefages f is uncertain, for there is little that is definite 
or that can be relied on in his treatment of the Hesionide, as, 
indeed, Claparéde long ago pointed out. In the number of 
the tentacular cirri Tyrrhena agrees with the genus Fallacia 
of De Quatrefages, but this is all that can be said with 
safety. 
Though the species had long been discriminated in my 
collection, the publication of the Annelids of the ‘ Caudan’ by 
Prof. Louis Roule gives his title priority. His single example 
was procured in the Atlantic at a depth of 1410 metres. In 
his description no allusion is made to the cuticular lens of the 
anterior eye. He correctly points out the distinctions from 
Tyrrhena Claparédit in regard to the tentacular cirri and the 
teeth. His account of the dorsal bristles, however, requires 
further elucidation, for he states that they are of two kinds, 
viz., a rare form, which is simple and delicate, tapering to a 
curved point; the other the camerated bristle, which at its 
tip has a cap of granular matter, giving it the aspect of a 
racquet. In that from the ‘ Porcupine’ not a few of the 
dorsal bristles had a granular parasitic mass near the tip, as, 
indeed, is liable to happen in spiked bristles. That the type 
of bristle should be so altered (as shown in Prof. Roule’s right 
* Annelids of the ‘Challenger,’ p. 186, pl. xv. a. figs, 5-7. 
+ Ann. Chét. Nap. p. 227. 
{ Annelés, pp. 95-111. 
