638 Zoological Illustrations : — 



habits I impute to the mackerel ; though I am aware I am 

 comparing a freshwater fi-sh to a saltwater one. When the 

 char spawn, they are seen in the shallow parts of the rocky 

 lakes (in which only they are found), and some of the streams 

 that run into them ; they are then taken in abundance : but 

 so soon as the spawning is over, they retire into the deepest 

 parts of the lake, and are but rarely caught. Such, I venture 

 to suppose, may be the habits of the mackerel. This opinion 

 is offered with deference ; and it would be a gratification to 

 have it confirmed by some who may have more opportunities 

 for pursuing the enquiry than I have. 

 Clapton, Sept. 1834. 



[Our correspondent's opinion is quite in accordance with 

 that of a naturalist distinguished in his knowledge of fishes ; 

 who, farther, sees in the law of nature which impels fishes to 

 visit the shores periodically, a beneficent provision for the 

 welfare of man, who, without the action of this law, would be 

 deprived of many of those most valuable to him as food. 



Our correspondent, the Rev. W. B. Clarke, has mentioned 

 unusual dates of the appearance of mackerel, and other species 

 of fishes, in VI. 291, 292., VII. 197., in his collection of facts 

 relative to his arguments in proof of his proposition of the con- 

 nection of meteoric phenomena with volcanic emanations.] 



Art. V. Illustrations in British Zoology. By George John- 

 ston, M.D.J Fellow of the Royal College of Surgeons of Edin- 

 burgh. 



26. Rete'pora cellulo^sa. {Jig. 69.) 



Synonymes. — Retepora eschara marina Ellls^ Coral]., p. 72, pi. 25. fig. d. 

 D. F .; Millepora Retepora Pall.^ Elench., p. 243. (exclus. Syn. Rail syn.) ; 

 Millepora cellulosa Lm., Syst., p. 1284.; Turt,^ Lin., iv. p. 637. (exclus. 

 syn. Borl. Cornw.); Turt.^ Brit. Faun., p. 205.; Stew.^ Elem., ii. p. 427. 

 M. foraminosa Soland.y Zooph., p. 138. pi. 26. fig. 2. Retepora cellulosa 

 Lam.y Anim. s. Vert., ii. p. 182.; RissOy I'Europ. Merid., v. p. 343. 



Rete'pora cellulosa has been long known as a production 

 of the Mediterranean, where, says Ellis, it is " found grow- 

 ing to shells and rocks, on the Italian shore, in irregular 

 leafy figures, but very often in the form of a cup or drinking- 

 glass, irregularly expanded at the brim." The British spe- 

 cimen here delineated has something of the latter form, and 

 is about an inch in height with a breadth of nearly three 

 quarters : it is affixed by a hollow, thick, and very short 

 stalk, which expands into a shallow cup, with unequal, waved, 



