A large nematocyst, with everted thread, is seen in the right-hand ectodermal cell.
(After Kleinenberg, from Gegenbaur.) access of water to the contents; when the cnidocil is stimulated it sets in action a mechanism or perhaps a series of chemical changes by which the plug is dissolved or removed; as a result water penetrates into the capsule and causes its contents to swell, with the result that the thread is everted violently.
B, The same, partially everted by eversion of the sides, as in the Nemertine proboscis and Gastropod eye-tentacle = pleurecbolic.
23 the proboscis is seen in an everted state; it is only so carried when feeding, being withdrawn when the animal is at rest.
A, Siphonal notch of the shell e, Everted buccal introvert (prooccupied by the siphonal boscis).
In Nemertines the everted proboscis is retracted in the same way as the tip of a glove finger would be if it were pulled backwards by a thread situated in the axis and attached to the tip. The comparison may be carried still further.
The central thread just alluded to is represented in the Nemertean proboscis by that portion which is never everted, and the tip of the glove by the boundary between the evertible and non-evertible portion of the proboscis - a boundary which in the Metanemertini is marked by the presence of a pointed or serrated stylet.
Proboscis is everted Partial extrusion lessening the resistor rhynchostome.
The colour is generally black-and-tan or brownish, the body is extremely long and cylindrical; the ears are large and pendulous, the legs broad, thick and twisted, with everted paws..
Fixation takes place by means of this sucker, which is everted for the purpose, part of its epithelium becoming the basal ectoderm of the ancestrula.
Where the whole crop is strengthened by a framework of bars, the incudate mastax lies in a little postero-ventral pouch which can be everted through the crop and mouth.
Starfishes devour large numbers; they are able to pull the valves of the shell apart and then to digest the body of the oyster by their everted stomach.
- Nearly related to the last, but the antlers still smaller, with shorter pedicles and divergent frontal ridges; upper canines of male not everted at the tips.
Copulatory organs are absent, except in the Apoda, in which a portion of the cloaca can be everted and acts as a penis.
They are of a dark brown complexion, with very broad noses, lips but slightly everted, and small but usually sturdy physique, though often considerably emaciated owing to insufficiency of food.
The peduncle of the Brachiopoda was supposed to correspond with the everted ventral sac of Actinotrocha, but the question is complicated by the want of any complete investigation of the development of the Brachiopoda, and by the absence of the anus in the majority of the genera.