TRANSACTIONS OF THK SECTIONS. 599 



1. The Actinia equina is nearly cylindrical, the upper margin 

 begirt by a triple row of 70 or 80 tentacula, with 30 or 40 

 purple tubercles at their root. A purple ring encircles the 

 base, and there are two purple patches on the mouth. All the 

 remainder is brown, speckled with green. Food is seized and 

 conveyed to the mouth by the tentacula ; smaller portions are 

 absorbed into the system without any visible residue : the 

 tubercles open to discharge purple flakes, after moderate sup- 

 plies ; but larger quantities are rejected in the form of a ball, 

 digestion having probably operated on the surface only. 



This animal is viviparous, though the fact is to be very 

 rarely witnessed. The embryos, one or more, appear first in the 

 tentacula, from whence they can be withdrawn, and transmitted 

 to others by the parent, and are at last produced by the mouth. 

 In the course of six years, a specimen, preserved by the author, 

 produced above 276 young ; some pale, and like mere specks, 

 with only eight tentacula, others florid, and with twenty. 

 They are frequently disgorged along with the half-digested 

 food, 38 appearing thus at a single litter. An embryo extracted 

 artificially from the amputated tip ofatentaculum, began to breed 

 in fourteen months, and survived nearly five years. Mon- 

 strosities by excess are not uncommon among the young : one 

 produced naturally, consisting of two perfect bodies, and their 

 parts sustained by a single base, exhibited embryos in the 

 tentacula at ten months, bred in twelve, and lived above five 

 years. While one body was gorged with food, the other con- 

 tinued ravenous. 



2. Hydra tuba, the trumpet polypus, thus denominated from 

 its form, inhabits the Frith of Forth, near Edinburgh, where 

 its natural abode seems the internal concavity of the upper 

 oyster-shell. Removed to an artificial site, it suspends itself by 

 its narrow base, while the long slender tentacula, above thirty 

 in number, descend two inches, to wave as a beautiful white 

 silken pencil in the water. Thus it is by much the largest of 

 the Hydrce. proper. 



This animal is alike voracious as the former. Its colour, 

 naturally a dingy white, is affected by the quality of the food, 

 and the fertility of both species is dependent on the quantity 

 of nutriment. The flesh of muscles seems that which is most 

 acceptable to many of the small aquatic animals. 



The embryo originates in a rude organic mass, as an ex- 

 ternal bud, near the base of the parent. Prominences above 

 soon indicate incipient tentacula surrounding the mouth, while 

 the lower part remains united by a ligament, which gradually 

 decreases until it is ruptured, as the embryo withdraws to esta- 



