124 BrR.]fA, ITS I'EOVLE A.XB PIWDVCTIOXS. 



Sub-Kingdom VI. MOLLUSCA. 



Soft-boiliod unsogmcntcd animals, with or without an external or internal 

 " shell." A stomach, intestine, and both oral and anal orifices, yexes distinct or 

 united. Reproduction by ova, but animals sometimes viviparous. The teetli are 

 minute, siliceous, and ranged symmetrically on tlie 'lingual rilibon,' radula or 

 ' odontophore,'' as it is more properly called. They are beautiful objects under the 

 microscope, and of value in classitication. 



Class BEACrilOrODA. 



Bivalves. Valves unequal, upper and lower, not right and left, as in ordinary 

 bivalves ; no elastic ligament, and lower valve often perforated a])ically to allow 

 the pa.ssage of a ten<linous peduncle for attachment to fixed substances. Gills none. 

 Radula none. A pair of ciliated oval arms, whereby food is obtained, but which 

 are not extensile beyond the shell. 



Famili/ Craniiclae. 



Ck.INIA .STELtA, RcCVO. 



Famili/ Lingulidae. 



LixGULA niAxs, Swuiuson. The Audamans. 



Of this species Capt. Wilraer writes (Proc. Zool. Soc. L. 1878, p. 820): "It 

 lives in mud or sandy clay at low-water mark, the shell being buried about a foot 

 from the surface. It is very easily alarmed, and retreats rapidly downwards. In 

 order to collect specimens I searched for oval orifices in the mud, and having fouiid 

 one, a spade was plunged very deeply in, and the mud turned over, the hands tlieii 

 being used to go deeper ; yet still in many cases the creature was too quick for the 

 diggers." 



,, (sp. near Anatina). 



A species of Lingula is sometimes brought for sale as food, to the Akyab bazaar 

 and merits our respect, for its ancient lineage, belonging as it does to a genus, which 

 may be said to have witnessed the dawn of life in the seas, and compared with 

 ■which man's birth on the planet is au event of yesterday. 



Class LAMELLIBRANCIIIATA. 



Bivalves. Yalves equal or unequal. Respiration by moans of lamelliforiu 

 branohiai. Radula none. Sexes distinct. The shells of females are often more 

 swollen than those of males, from the greater space required for their enlarged 

 ovaries. This disparity is sometimes so great in some Vnioncs as to have led to the 

 sexes being specifically separated. 



The young are hatclicd within the body of the parent, and are discharged in 

 cloud-like swarms of tiny creatures, to seek each its own living. Tlie embryos at 

 first swim freely about, in which stage they represent the permanent condition of 

 the Pteropoda, but soon dropping their filamentous organs of motion, as tadpoles do 

 their tails, they either attach themselves permanently to any convenient roosting- 

 place within their reach, as Odroa or Chama, moor themselves securely by a 

 ' byssus ' or cable, like Pinna or Jfi/filiin, or lead a free and roving life like Cardiiim 

 or Unio. " The body of the bivalve MoUusca is enveloped in a muscular mantle, 

 which is usually more or less united at the mai'gins, forming a branchial cavity with 

 three openings, a pedal, a bronchial or inhalent, and an excretory or anal, the pedal 

 orifice being situated anteriorly, and the others towards the hind part. The mantl(! 

 secretes the shell, the interior of which it lines, and to which it is fixed by tlie 

 adductor muscles, which pass through it to be attached to the body of the animal." 

 (Adam, 'Genera,' Vol. II. p. 318.) In some genera, as Odrea, the mantle is open, 



