. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TYPE M0LLU8CA. 323 ood reason, 5, why their iquatic Pro- ler hand, it eh as Cycio- Pulmonate )f closely. lionodenta- depths of poweis of ssessing a }:ated but n over to le Scaph- n'ked cou- from the ig arouud osteriorly fsally aud r wall of s open at rger than a tubular lly to that â ' if) Pi'o- n a cyliu- provided ylindrical proboscis )f lealiike ipou each B of being 'ithdrawii ed struct- mc -1 ure whose concave surface is furnished with ciliated cells and also towar
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TYPE M0LLU8CA. 323 ood reason, 5, why their iquatic Pro- ler hand, it eh as Cycio- Pulmonate )f closely. lionodenta- depths of poweis of ssessing a }:ated but n over to le Scaph- n'ked cou- from the ig arouud osteriorly fsally aud r wall of s open at rger than a tubular lly to that â ' if) Pi'o- n a cyliu- provided ylindrical proboscis )f lealiike ipou each B of being 'ithdrawii ed struct- mc -1 ure whose concave surface is furnished with ciliated cells and also towards the margin with unicellular glands. These structures have been supposed to represent the ctenidia of the other Mollusca, but this view cannot, in the present condition of our information concerning their structure and devel- opment, be accepted without reser- vation. The mouth opens into a short oesophagus provided with a single chitinous jaw- tooth apparently formed by a fusion of two chitinous masses, and behind this there is a pharynx provided with a raduia and opening posteriorly into the some- what U-rhaped more or less convolu- ted intestine (A which terminates in the anus (a) lying in the mid-ventral Hue behind the foot. Into the intes- tine at the turn of the U there open the ducts of the digestive gland (l), aud into the posterior portion of the Fig. 145. â Structure of intestine, the rectum, there open in DerUaUum (after letokart). IJentaUum several ducts from a rectal f<laud which surrounds this portion of the digestive tract and whose sig- nificance is quite obscure. The nervous system presents the niajoi-ity of the ganglia characteristic cf the Gasteropoda, and the pleuro- vis(;eral connectives do not cross one another. The cerebral ganglia (ce) lie at the base of the proboscis an- terior to the cesophagus and have closely associated with them the pleural ganglia, the cerebro-pedal and pleuro-pedal connectives fusing with one another to pass downwards a
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1896
