ANATOMY oK PELECYPODA BURNE. 



OSTILKACKA. 



LIMID^B. 



Lnihi (Limatula) liodijsntii. Smith. 

 Station 331. Smith (18). p. 77. 



EULAMELLIBRANCHIATA. 



ST li.MYTILACEA, CAKDITID^. 



Venericardia />ur/>tn;it<t (J)eshaves) ( Vfn<-rinir<H<i in/xti-it/i*, Lunik. '.). 

 Si. -i I ion 134. Smith (18). p. io. 



VKNEKACEA, VENKK I I >. K 



Chione (Chamelea) *///'*.></ (Deshaves). 

 Station l:',4. Smith (18), p. '.)(). 



ANATINACEA. A N ATI M D/R 

 A/Htfi/xi <'///'////'<</. King and Broderip. 



Off Oape Evuns, McMurdo Sound, in 5 futhonis. Smith (18). p. 7s. 



IV-ANATOMICAL DESCRIPTIONS. 



FILIBRANCHIATA. 



ARI'ACKA. ARCID.E. 



1. Lisxai't-ii notorcadensis, .Melv. und Stand. PI. I, figs. 1-7. 



Stiition 331. Numerous specimens (in two srp:ii',-itc liottles) dri-di^vd tVom tin.- 

 cntnuice to McMurdo Sound, in iTiO fatlioms. The specimens in one of the liottles 

 were clustered upon u piece of weed, firmly attached to it liy their liyssns. 



It will lie seen from the diagram. PI. I, fi^. 1. that in generul the animal 

 approadies in structure to the tvpc characteristic of the Areas, though the unterioi' 

 adductor, instead of liein^ as in some species of the familv merelv reduced in si/.e. is 

 entirely absent. 



Mantle. The mantle is open from end to end. Its border is ijinte simple, without 

 tentacles or eye-spots. In section it shows three, simple folds, as in other members of 

 the family. The middle of these (ti^. _'. ///./'.). which secretes the periostraciun. j.< V cry 

 slightly expressed, the inner (/./'.) is thick and swollen. 



M 11.11-1, x. -There is only one adductor (the posterior), the anterior being entii-elv 

 absent. Tliei'c ure ihi'ee pairs of pedal muscles t \\ o anterior and one posterior. (If 

 these the po>tcrior relructors arc the larvesi aiicl most powerful (though much |cs< so 

 than in mosl Areas) and are inserted almost entirely mlo the byssal papilla. The 

 anterior retractors (JML;'. I. <t.r./>.) occiip\- the usual position between the oesophagus 

 and the cerebral ganglia ; the oher pair of muscles (''/') i'i" ele\atores pcdis. which 



