418 STHBNBLAIS LIMICOLA. 



stouter series follows, also with long bifid tips, the shafts becoming more slender in the 

 lower group. Lastly is a more delicate group at the ventral edge, having bifid distal 

 appendages of from five to ten articulations. The ventral cirrus is long and tapering, 

 with a terminal segment. 



Synonyms. 



1853. Aphrodita arcta, Dalyell. P.ow. Creat., ii, p. 170, pi. xxiv, f. 14. 



1864. Sthejielais limicola, Ehlers. Borstenw., 120, Taf. iv, f. 4—7 ; Taf. v. 



1868. „ leiolepis, Claparede. Ann. Chet. Nap., 96, pi. iv, f. 3, and pi. vi, f. 1. 



1869. „ limicola, Mcintosh. Trans. R. S. E., xxv, 410. 



1875. „ „ idem. Invert, and Fish., St. A., p. 118, 



1876. „ „ idem. Trans. Z. S., ix, pp. 390, 476, pi. lxx, f. 13. 

 1884. „ „ Y. Carus. Faun. Medit., p. 205. 



1891. „ „ Hornell. Op. cit., p. 238. 



1895. „ „ Pruvot and Racovitza. Arch. Zool. exper., p. 473, pi. xx, f. 122, 123. 



Habitat. — First dredged by Dr. Grwyn Jeffreys in sixty to eighty fathoms off 

 North Unst, in St. Magnus Bay, and the Outer Haaf, Skerries, in Shetland in 1867. It 

 is very abundant off St. Andrews, probably in sand, and is tossed on shore in large 

 numbers during certain storms. While it is not common in the dredge, the cod seems 

 to find it readily, and so do the flounder and other fishes. In the 'Porcupine' 

 Expedition of 1869 it occurred in 30 to 370 fathoms off the Irish coast, and a small 

 eyeless variety in 420 fathoms. It ranges from Shetland to Cornwall, and has been 

 found chiefly in water of some depth, — never, at any rate, between tide-marks. It 

 extends likewise to Norway (Canon Norman), to Quarnero in the Adriatic, to the shores 

 of Canada, and the United States of America. 



Head (Plate XXIX, fig. 3) somewhat ovoid in outline, with the long diameter 

 transverse. The median space is marked by a brownish crescentic line on each side, 

 which Ehlers compares to an H. The posterior pair of eyes are situated a little behind 

 the base of the median tentacle, are of considerable size, and sometimes show a pale 

 speck in the centre, as if from a corneal lens. The anterior pair are scarcely visible 

 from the dorsum (indeed, they escaped Ehlers), being situated under the lateral 

 processes (ctenidia) at the base (ceratophore) of the median tentacle, and looking 

 straight forward. They are somewhat larger than the posterior, and also occasionally 

 show a pale speck in the centre. The ceratophore of the median tentacle is somewhat 

 conical in spirit, but Ehlers says cylindrical in life, and from it a tapering tentacle 

 (ceratostyle) of moderate length passes. The filiform region shows a slight enlargement 

 at the tip in spirit, and a trace of an articulation at its commencement. On each side of 

 the base is a flattened spatulate process (ctenidium) with long cilia. The frontal lobe 

 carries ventrally the very long, tapering, smooth palpus, with a small sheath or 

 membranous collar at its base internally, then a slender filiform ventral cirrus ; dorsally a 

 much larger dorsal cirrus, and internally to the ventral cirrus a broad scimitar-shaped 

 process (cuilleron cephalique, Pruvot and Racovitza). A little behind and internal to the 

 dorsal cirrus is the tip of the lateral tentacle, which Racovitza followed backward to its 

 attachment to the head. In his description Ehlers omits the scoop-like process at the 



