EUNOA NODOSA. 295 



straighter forms being external, that is, next the ventral. The tips have the character 

 shown in fig. 24, Plate XXXVII, viz. less tapered than in E. wrstedi (Plate XXXVII, 

 fig. 25) — with a shorter smooth portion and more boldly marked spinous rows. 



The ventral bristles (Plate XXXVII, figs. 22 and 27), on the other hand, have pro- 

 portionately longer spinous regions superiorly than in E. wrstedi ; the tips are more 

 distinctly hooked, and the bare portion is broader on an average than in the species just 

 mentioned (Plate XXXVII, fig. 23). The latter is not what might have been expected 

 from the condition anteriorly. The ventral cirrus extends a little beyond the inferior 

 border of the foot. 



Posteriorly both dorsal and ventral bristles become more attenuate, as well as smaller, 

 in conformity with the diminished feet, but they do not assume the elongate and slender 

 condition observed anteriorly. 



Two very large examples from the stomach of a cod agree with the fine Zetlandic 

 specimen in having the smooth tips of the dorsal bristles somewhat shorter. On the other 

 hand, young specimens (about J of an inch) have longer tips to the dorsal and ventral 

 bristles, and the scales are more rounded and have proportionally thicker cilia. 



While the scales in the examples from Spitsbergen agree in shape and structure 

 with those from the Gulf of St. Lawrence and Britain, the dorsal bristles have 

 assumed a more elongated condition, so as to resemble those of E. aerstedi, being 

 more tapered, and with a longer bare portion at the tip ; yet the general curve of these 

 bristles is more pronounced than in E. wrstedi. The tips of the ventral bristles are also 

 proportionally longer than in the ordinary type. The typical characters of E. nodosa 

 are seen in examples from the Arctic seas (Greenland), where the species attains a large 

 size. The distinctions between the two forms are therefore evident, but whether two 

 species should be formed may be to some an open question. 



A parasitic sponge, with long processes, occurs on a scale of the example from 

 Cumbrae. 



Habits. — So far as can be ascertained, the present form is only found in deep 

 water off the British shores, and that but rarely. It is more abundant in the northern 

 seas of both Europe and America. Loxosomse abound on the feet and bristles of those 

 from the Gulf of St. Lawrence. 



Reproduction. — The only example of the genus observed with fully developed 

 reproductive elements is a large female of E. oerstedi, from Greenland, distended with 

 ova, and probably procured in July. 



This is one of the many forms that marine zoology owes to the industry and keen 

 observation of the elder Sars, who patiently explored the shores of his native country 

 for so many years and with such remarkable success. 



It is difficult to know to what Sir J. Dalyell (1853) 1 refers under the name of 

 Aphrodita squamata, from Shetland, unless it be this species. Theel (1879) noted that 

 Eunoa nodosa and E. aerstedi, Malmgren, were the same species, viz. the Lepidonotus scabra 

 of (Ersted, an opinion coinciding with the remarks made by myself many years previously. 

 He procured large examples (70 mm.) at a depth of 90 — 200 metres in the Kara Sea (Nova 



1 ' Pow. Creat./ ii, 166, pi. 24, f. 3, 4. 



39 



