190 ACANTHOPTERYGII. 



Ventral consists of one badly developed spine imbedded in the skin, and four 

 rays, tbe inner of which is connected with the lowest of the pectoral. Between 

 the ventral fins and extending posteriorly to the middle of the length of the 

 fish exists a large suctorial disc which is composed of two portions separated 

 one from the other by a deep groove. The entire organ can be employed as one 

 sucker, the skin covering the onter bnt inferior matgin of which, is modified 

 into irregularly shaped flattened points, extending on to the under surface of 

 the three outer ventral rays, which thus constitute a portion of the disc. As 

 already observed, the large disc is subdivided into two, the anterior being 

 connected with the base of the ventral fins but separated by a deep transverse 

 gi-oove from the posterior portion of the disc. The ventral portion extends 

 anteriorly towards the throat, where it is formed by two layers of skin passing 

 from the base of one ventral fin to the other, the inner or lower layer having 

 a thickened pavement-like appearance as already described, and which is con- 

 tinued on to the three outer ventral rays ; the centre of this portion is a 

 smooth pad. The posterior portion of the disc has for its groundwork cartilaginous 

 expansions from the radius (Owen or coracoid, Parker), its centre is a soft 

 smooth pad similar to that observed in the anterior portion, while the whole 

 of its circumference, is formed of two layers of skin forming a free edge : 

 the lower layer being thickened and modified into flattened nodules as already 

 described, and just at its posterior margin fine ray-like prolongations of the 

 cartilage are visible. Skin slightly loose but tough. Colours — usually carmine 

 or purplish red, becoming lighter on the under surface. In some, however, the 

 ground colour is brown or green. Two or three yellow dark-edged interorbital 

 bands are usually present : and two large oval, sometimes pyriform, black 

 ocelli on the occiput surrounded by two lighter rings. Some have oblique blue 

 stripes on the body. Risso observes that no external differences are perceptible 

 between the males and the females. 



Varieties. — The colours widely differ, occasioning some authors to constitute 

 several different species. L. Gouanii, Risso, is greenish with dark spots, 

 but no blue markings. L. halbis, Risso, has two dark red spots on the 

 side of the neck. L. biciliatus, Risso, is green with blue or brown spots 

 and marks. L. zebrinus, Lowe,, is blackish brown, the sides being posteriorly 

 marked with oblique blue stripes : the neck having divergent cross streaks and. 

 a pair of pear-shaped blotches. In the Ordnance Survey of the county of 

 Londonderry, two examples of a rich blue colour are alluded to, with deeper 

 tinted postocular spots. 



Names. — Jura sucker by Pennant, due to his having first obtained it at Jura 

 in the Hebrides : Cornish sucker, owing to its being common in Cornwall. 



Habits. — Resides under stones in pools between the tide marks, where it 

 can firmly attach itself to stationary or suitable objects. It is inactive, its 

 movements being a species of wriggle. Montagu remarked that although it is 

 sluggish it seems to wander, sometimes being abundant, at other times rare. 

 It is tenacious of life. Gouch observes that its food is the smaller crustaceous 

 and marine insects which it swallows whole. 



Breeding. — About March or April, when it deposits its ova inside the dead 

 shells of oysters, scollops, or other bivalves. Couch says the grains of ova are 

 of considerable size in proportion to the bulk of the fish. 



Habitat.— Extends from Denmark along the coasts of Great Britain, 

 Ireland and France where it is common in some localities, to Spain, Portugal, 

 Teneriffe, and Italy, where, however, it is not common. In fact it may be said to 

 be rare in the Mediterranean. Orkney and Zetland, one example obtained in 

 Scalpa Plow, in the winter of 1850, by Mr. J. Syme (W. Baikie), Jura in 

 the Hebrides (Pennant). Aberdeen, where one local example is in the possession 

 of Mr. Sim. Montagu considered it to be common at Milton, in Devonshire : 

 Borlase obtained it in Cornwall, and Mr. Cornish observes that in Cornwall 

 it is common under stones and in small pools by the sea shore. I have received 

 it from Mr. Dunn of Mevagissey, and many examples from Mr. Carrington, f.l.s., 

 which he collected in Guernsey. 



