MOLISE 



MOLLUSCA 



259 



Jesuit preacher Segneri was the first who ven- 

 tured pulilicly to call them into question. By 

 degrees reports unfavourable to tlie practical results ! 

 of this teaching, and even to the personal conduct 

 and character of Molinos, or of his followers, began 

 to find circulation ; and eventually, in the year 

 1685, he was cited before the Holy Office, and sub- 

 mitted to close imprisonment and examination. In 

 addition to the opinions contained in his book, a 

 prodigious mass of papers and letters, to the num- 

 ber, it is said, of 20,000, found in his house, were 

 produced against him, and he was himself rigor- 

 ously examined as to his opinions. The result of 

 the trial was a solemn condemnation of sixty-eight 

 propositions, partly extracted or inferred from his 

 X/Hi-itiHil Cinilr,, partly, it would appear, drawn 

 from his papers or Iris personal professions. These 

 doctrines Mulinos was required publicly to abjure, 

 and he was himself sentenced to close imprison- 

 ment, in which he was detained until his death, 

 2stli December 1697. The opinions imputed to 

 Molinos may be described as an exaggeration of 

 the principles of Quietism (q.v.) the utter in- 

 difference of the soul, in a state of perfect con- 

 templation, to all external things. See John 

 Bigelow's Mo/inai the Qnietint ( New York, 1882); 

 J. H. Shorthouse, Golden, Thoughts from the 

 Spiritual <l,,;,tc (1884). 



Molise. See CAMPOBASSO. 



Mollall. among the Turks, is the title of a 

 superior judge. The mollah is an expounder of 

 civil and criminal law, and of the religion of the 

 state ; he is therefore necessarily both a lawyer 

 and an ewlesiastie. Under him is the cadi or judge, 

 wlio administers the law. 



Mollrixlo, a port of Pern, lying SW. from 

 Lake Titicaca. It has railway connection with 

 Puno (346 miles) by a line passing Arequipa (107 

 miles), and enjoys considerable trade; but there is 

 no other inducement to reside there, and the popula- 

 tion is only 1500. 



Molllisrn. a large division of invertebrate 

 animals, including three chief classes : bivalves or 

 I-aniclliliranchs, 'snails' or Gnsteropods, and cuttle- 

 fish or Cephalopoda. As these are separately dis- 

 cussed, it will ! enough to state the general char- 

 acters and classification of the series. 



Getifi-nl I'linri'Hrrx. Though most cuttle-fish and 

 not a few gasteroi>ods are free swimmers, the aver- 

 age habit of molluscs tends markedly to sluggish- 

 ness, and with this the calcareous shell of the great 

 majority may lie naturally associated. Most of the 

 gi-nrra are marine, but there are many fresh-water 

 forms ( proliably originating 'from the conversion 

 of shallow continental seas into lakes'), while the 

 species of terrestrial snails and slugs are legion. 

 As to diet, the sluggish bivalves feed on micro- 

 scopic animals and organic debris wafted to the 

 mouth by the gills; the gasterojiods are divided 

 into carnivores and vegetarians, omnivorous glut- 

 tons ami dainty epicures ; and the cephalopods 

 are voracious llesli-eaters. In this connection the 

 absence of a rasping tongue in the bivalves, and its 

 presence in all the others should be noticed. 



One of the most conspicuous structural charac- 

 ters is the absence of the segmentation and the 

 serial appendages which characterise the arthro- 

 pods and higher 'worms.' The typical mollusc 

 is bilaterally symmetrical, as may be seen in bi- 

 valves and in those gasteropods of which Chiton 

 (q.v.) is a representative, but in the majority of 

 gasteropods the Imdy is markedly lop-sided. This 

 condition is referred l>y Lankester to the exag- 

 gerated vertical growth of the viscera into a dorsal 

 blimp surmounted by a shell, which in creeping 

 animals will tend to fall to one side, and thus pro- 

 duce torsion. With the skin, which is soft and 



glandular, and often ciliated, two very character- 

 istic structures are connected on the dorsal surface, 

 the one a small pit constant in the embryo the 

 primitive shell-sac or shell-gland; the other a fold 

 of skin overlapping the sides and forming the 

 'mantle.' From the latter a very varied perma- 

 nent shell is usually formed as a cuticular product 

 coin|Mised of carbonate of lime and an organic basis. 

 Its thickness seems often to bear some relation to 

 the external and internal activities of the mollusc, 

 for it is thin in the active scallop (Pecten) and 

 Lima, thick in the passive oyster and Tridacna, 

 slight or iilisi'iit in the pelagic Pteropods (sea- 

 butterflies) and in the active Cephalopods, but 

 heavy in most of the slowly creeping littoral forms. 

 But that this is only one condition of shell- develop- 

 ment is evident in many ways for instance, when 

 we compare land-snails with slugs; for the latter, 

 though hardly less sluggish than the former, are 

 practically shell-less. Another very distinctive 

 structure is the n.iilluscan ' foot,' a muscular pro- 

 trusion of the ventral surface, usually locomotor 

 in its function, but turned to various uses, and 

 degenerate in the most sedentary bivalves, especi- 

 ally in the oyster. 



As to the less obvious general characters, the 

 nervous system consists typically of a pair of cere- 

 bral ganglia, connected to a pair of pedals and to 

 a pair of pleurals, the latter associated with a 

 visceral nerve-loop which may also be ganglionated. 

 In the cephalopods, and in most gastcropods, 

 the three chief pairs of nerve-centres are closely 

 united in the head, but in the symmetrical chitons 

 a much more primitive, and in the bivalves a much 

 less concentrated arrangement obtains. The sense- 

 organs vary greatly, but there may be tentacles 

 like the snail's 'h'orns,' head-eyes like those so 

 well developed in most cuttle-fish, while a pair of 

 ear-sacs or otocysts in the front of the foot and a 

 smelling-patch or ospliradium at the base of the 

 gills are all but constant. On the edge of the 

 mantle of many bivalves, or penetrating the shell- 

 plates in Chiton, there is quite a plethora of eyes, 

 some of which are imperfectly visual and possibly 

 light-absorbing in function. The food -canal includes 

 in the mouth-region a toothed ribbon, absent in 

 bivalves, and bears further back a digestive gland 

 often of large size. The long coils of the gut are 

 depressed ventrally into the foot of bivalves, and 

 are protnided as if in a hernia on the dorsal surface 

 of most gasteropods. The heart, absent only in Den- 

 talium and related genera, lies dorsally in a special 

 ]x>rtion of the body-cavity known as the pericar- 

 dium, and drives colourless blood through the body, 

 thence into the gills and kidneys, whence it returns 

 purified. The gills are vascular outgrowths of the 

 Body-wall, usually sheltered by the mantle, which 

 in the terrestrial forms like the snail makes a lung- 

 like chamber. A paired or single kidney connects 

 the pericardium with the exterior. The reproduc- 

 tive organs unisexual or hermaphrodite vary ex 

 tremely, from great simplicity in most bivalves to 

 an extraordinary degree of complexity in many 

 gasteropods, such as the snail. 



In their life-history most molluscs pass through 

 two larval stages. The first is a somewhat barrel- 

 shaped form, with a ring of cilia in front of the 

 mouth ; it is known as a trochosphere, and is quite 

 like the young stage of many ' worms." This passes, 

 however, into another more characteristic phase 

 called the Veliger, which bears on its head a cili- 

 ated area or locomotor ' velum ' often produced into 

 lobes, has its Ixxly already characterised by a vis- 

 ceral hump and a ventral foot, and possesses on 

 its dorsal surface the little shell-gland already 

 mentioned. In the cephalopods, whose ova are 

 rich in yolk, the trochosphere and veliger stages 

 are skipped over, and there are also notable 



