64 



MOLLUSCA. 



[Gasteropoda 



3. Patella Forbesii, Supplementary plate, f. 1,2. 

 Patella Forbesii, Smith, Wernerian Mem., VIII, p. 59, pi- 



2, f. 3, 3* 



Shell thin, pellucid, obovate, gibbous, orange-coloured ; with 

 regular, longitudinal, tuberculous stria?; vertex inclined, inflect- 

 ed. Length two-tenths of an inch ; breadth one-eighth. 



" The regular, tuberculated, longitudinal stria:, radiating from 

 the submarginal apex, at once distinguish this species from any 

 of its allies among the British Patella?. In form it resembles 

 the Lottia pulchella. The margin behind the apex is trun- 

 cated, and the colour of the shell is orange-yellow. When the 

 animal shall have been examined, it may prove to be a Lottia." 

 Forbes. 



Dredged in Rothesay Bay, by James Smith, Esq., of Jordan 

 Hill, adhering to a case-bottle in ten fathoms water. 



4. Patella pellucida, pi. XX, f. 2, 3, 7, 8, and 11. 

 Patella pellucida, First Ed., pi. 37, f . 1 1 ; Linne, Syst., p. 



1260; Da Costa, p. 7, pi. 1, f. 5; Pennant, p. 150, pi. 90, f. 

 150, right hand fig., and f. 152, bottom fig.; Patella lesvis, 

 Lamarck, VI, pt. 1, p. 334 ; Da Costa, p. 7, pi. 1, f. 5 ; Mon- 

 tagu, p. 474 ; Maton and Rackett, p. 233 ; Brown, Wernerian 

 Mem., II, p. 538; lb., Ency. Brit., p. 465; Fleming, Brit. An., 

 p. 287; lb., Edin. Ency., p. 65, pi. 204, f. 2, 3, young; Turton, 

 Brit. Fau., p. 197 ; Forbes, p. 36. 



Shell smooth, subpellucid, thin, yellowish-green ; back con- 

 vex, elegantly rounded; with an inclining vertex, which is placed 

 nearer one end ; from the superior portion behind the vertex 

 emanate a series of beautiful azure-blue, translucent, interrupt- 

 ed rays, irregular in point of number, varying from three to 

 seven, and terminating on the margin ; some nearly obsolete, 

 concentric wrinkles traverse the shell ; aperture oval ; margin 

 plain, inclining slightly upwards at both ends; inside glossy, of 

 a bluish opalescent cast of colour, changing in hue according to 

 the play of light. Length one inch ; breadth nearly three- 

 quarters ; height five-eighths. 



Patella elongata and Patella parva, Fleming, Edin. Encv., 

 p. 65, pi. 204, f. 2, 3 ; (pi. XX, f. 2, 3, and 7) Patella bima- 

 culata, Montagu, p. 482, pi. 13, f . 6 ; Turton, Brit. Fau., p. 

 197 ; Maton and Rackett, p. 235. (pi. XX, f. 7.) 



The young shell, pi. XX, f. 2, 3, 7, 8, is extremely thin and 

 brittle, and of a much paler colour than the adult, usually of a 

 yellowish horn-colour. 



This species inhabits most of the coasts of Great Britain and 

 Ireland, generally adhering to the Fucus digitatus, algce, and 

 other marine plants. 



Much difference of opinion exists respecting this and the fol- 

 lowing shell being of one species. As far as my observation 

 has gone, I am inclined to consider them as different ; because 

 I have met with shells of all ages, agreeing with each in its 

 specific distinctions. The young of the following species is 

 invariably thicker, and always depressed like the adult ; and, 

 moreover, the P. pellucida is always found on the leaves of the 

 plants, while the P. cm-idea inhabits the stems or roots. 



My friend William Nicol, Esq., of Edinburgh, has a most 

 perfect series of both shells, from the very youngest condition 

 to the most mature, which beautifully illustrates the subject. 



At the meeting of the British Association, held at Manches- 

 ter, in 1842, Mr. Peach, of the Preventive Service at Ghoran 

 Haven, Cornwall, read a Paper, and exhibited specimens to 



prove their identity, but I did not think he established his 

 views on the subject. 



5. Patella cjerulea, pi. XX, f. 13. 



Patella ccerulea, First Ed., pi. 37, f. 13; Fleming, Edin. 

 Ency., VII, p. 65, pi. 204, f. 1, adult, 1 a, young shell; Pen- 

 nant, pi. 90, f. 150, left hand fig., young; Brown, Wernerian 

 Mem, p. 533; lb., Ency. Brit., p. 465 ; Forbes, p. 36; Mon- 

 tagu, Sup., p. 152 ; Patella pellucida, Montagu, Sup., p. 475 ; 

 Donovan, I, pi. 3, f. 1 ; Maton and Rackett, p. 234, the adult 

 shell; Da Costa, pi. 1, f. 6. 



Shell depressed, rather opaque, thick, slightly ovoid, of a 

 yellowish-brown colour ; vertex flat, much rounded, and situate 

 near to one end ; concentrically wrinkled, with a series of pale 

 azure-blue, shining, interrupted radii, which extend from the 

 vertex to the base, and generally, also, on the sides ; aperture 

 subovate, opalescent, shining, blue internally ; lips rather thick- 

 ened. Length one inch ; breadth eight-tenths ; height five- 

 tenths. 



Inhabits most of the British and Irish coasts, attached to the 

 stems and interstices of the roots of alga", Fucus digitatus, &c. 



Genus 17. — Lottia. — Gray. 



Shell patelliform, rather depressed ; vertex obtuse, for the 

 most part placed considerably towards one end, pointing to the 

 posterior margin ; muscular impressions not symmetrical, but 

 widest on the right side, towards that portion of the shell where 

 the head of the animal is situate; aperture generally rather cir- 

 cular ; the central disc usually of a deep brown, variable in 

 intensity; with a flattish internal margin. 



The shells of this genus so closely resemble those of Patella, 

 that they are with difficulty distinguished. They are, however, 

 generally flatter. The animal is very distinct from that of Pa- 

 tella. 



1. Lottia testudinalis, pi. XX, f. 9, 10. 



Patella cli/peus, First Ed., pi. 37, f. 9, 10; Patella testudi- 

 nalis, Miiller ; Fabricius, Fau. Greenland, p. 385 ; Forbes, p. 

 34; Patella Clelandi, Sowerby; Smith, Wernerian Mem., VIII, 

 p. 43. 



Shell oval, subdepressed ; with numerous, fine, divergent, 

 slightly waved, and rather regular stria?, emanating from the 

 slightly acute, reflected vertex, and terminating on the mar- 

 gins ; these are crossed by extremely numerous, and very 

 close, concentric stria?, and somewhat distant, more conspicuous 

 lines of growth ; external surface of a pale fawn colour, beau- 

 tifully mottled with dark, reddish-brown, surrounding oblong- 

 ovate, rather regular eye-like spots of the ground colour; inside 

 very glossy, bluish-white; margin a little flattened, and orna- 

 mented with nearly equidistant, dark brown spots; centre with 

 an intensely dark, reddish-brown, well defined, large mark, sur- 

 rounded by an indistinct disk of pale brown. 



First discovered as British by Stewart Ker, Esq., in the Gare 

 Loch, on the Clyde, and has since been met with in different 

 parts of Argyleshire ; and Professor Forbes found it at Bal- 

 laugh, Isle of Man, under the surface of stones at very low 

 water. 



2. Lottia pulchella. 



Lottia pulchella, Forbes, p. 35 ; lb., Mag. Nat. Hist., VIII, 

 p. 591, f. 61. 



