MON()(!UAPII 01-' DIUTISII LAN]) AND FliliSIIW ATHIi MoLIJ'SCA. 



Family IJMACFD.K Cray. 



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/U<A..^?^. 



Tlie liiiiiily LiiiKiriilir n,s liere iDnlerstiKid 

 eiiiliraccs the genera Li)i)ii.r,A/ji-io/l/ii(i.r 

 and Amalia, in additinn tn other gnmjis 

 foreign to our shores, ami altlioiigli now- 

 restricted in extent is not (>ven yet a 

 tliorongldy lioniogenenns faniiljr, l)ut the 

 parallel course of shell degeneration and 

 the marked convergence of the external 

 form of the constituent genera renders 

 their association convenient, at least 

 until their true genetic relationships 

 have heen elucidated. 



The great advances made in latcj-ears 

 in our knowledge of these neglected 

 creatures is largely duo to the hrilliaut 

 researches of l)r. Sinnrith, the eminent 

 German liniacologist, who has for 3'ears 

 made the elucidation of this group an 

 especial stinly. 



Family Characteristics.— Externally, the features possessed in com- 

 irron b)^ the Liinacidiv are the elongate, subcylin(h'ical body ; a more or less 

 noticeable dorsal keel, most pronounced at the caudal end ; an anterior 

 mantle or shield which covers the pulmonary chamber, the heart, the kid- 

 ney, etc., with the respiratory aperture on the right side, behind the 

 mi(hlle of tlie mantle margin ; sole longitudinally trijiartite, mid-area loco- 

 motor^r ; REPRoDrcTouY (lUii'tno behind the right minuatophore. 



811ELL oblong 01- oval, wliite and slightly concave, with tlie nucleus at the 

 ])osterior margin, but inclining towards the left side, from whence concenti-ic 

 lines of grciwth extend, which demonstrate that the external shell of whii-h it 

 is the vestige was spirally coiled: the Dendrolimaces of 8outh Afii'ca show- 

 more clearly the stages lietween the shelled and the naked species. 



Intei!NALLY, the nervous system is chiefly aggregated around the 

 pharynx'; an important caudodorsal nerve arises from tlie ]-iallio-abdominal 

 commissure, extends along the length of the body, and is in intimate con- 

 nection with ihe pharyngeal retractor; mandiule oxygnathou.s- ; lingual 

 TEETH numerous, arranged in median, lateral and marginal series and quite 

 typical of the group Dichoglossa"; pharyngeal and tentacular retr.actors 

 combined posteriorly and forming a common stem aftixeil to the dorsal 

 integument behind the lung, and constituting with the testaceous forms 

 the group Moiiorhiza.^ 



The Lhn((ci(hv is one of the groups which retain in adult life the jirind- 

 tive shell or pi-otoconclr""' formed by the shell-gland of the embryo: and 

 which also develoji in the dastrnla,'' stage a w-ell-markeil caudal vesicle, 

 whose rhythmical contractions assist tlie circulation of the body fluids prior 

 to tlie developing heart becoming functional 



The shell is the lapis Ihnacum of tlie Koma.ns, and enjoyed great re- 

 nown amongst the various remedies," bezoars, and amulets'' wfiich ancient 

 peoples held in high esteem either as specifics f-jr the cnre of various ail- 

 ments or as charms protecting the wearer against accidents or disease. 



1 IM, 



21.5, r. 1-21 

 I. 6:!7. 



271, f, 54:; 



