E^li.-i;i, Citllostrncum, Mesalia, ifc. .'571 



1801. Aa'rM suhdfnin»(ita : Locnrd, Coq. >fftriii. Fraiirn, p. ll'S, fi^'. 1 12. 

 18'J7. Hcalaria (Acirsa) tuhdecusaatu : WaUiun, Joiini. Limi. Sue. 

 vol. xxvi. p. 315. 



Ilab. Atlantic coj'sts of Franco an<l Spain, Mediterranean, 

 ^ladi'ira, and (Janaiie.s. 



I liavc conipart'fl the ty|)('s of Tnrritdla incisa. Reeve, 

 recordfd as tVt)ni Sydney, Australia, and Mt-.sd/ia sirintn, 

 A. Adams, stated to l)e iVom tin; Piiilijipiiu; Islands, with 

 Mftliterran«'nn and Madciran spcciniens, and I am convinced 

 of their identity. I there fore regard the localities given by 

 Ueeve and Adams merely as fuither examples of errors of 

 tliis kind which occur in the Cuinini^ collection, from which 

 the s|)<-cies were desciihfd. It is included in Mr. \Vhitel<'gi;o's 

 li.st of the fauna of Port Jackson* merely on Itccve'.s 

 authority. 



According to Monterosato, the animal of this species 

 resenililes IScalaria in the position of the eyes and the form 

 of the tentacles, also in t;ie median loncritudinal (groove of 

 the foot. The head has no cylinilrical and retractile proboscis. 

 He described the operculum as horny, with a spiral nucleus, 

 placed towartls the inner side of the mouth, and composeil 

 of a small nuu)ber of whorls and marked witli strong lines of 

 growth. Fischer also described the operculum as pauci- 

 spiial, with a lateral nucleus like that of b'ca/an'a and Li/fo- 

 rina. It will thus be seen that it agrees with that of the 

 type of Mesa/la (.)/. brevlalis), which is incorrectly fi^rnretl 

 as multispiral with central nucleus by II, & A. Adams (Gen. 

 Rec. Mcll. vol. iii. pi. xxxviii. ligs, -ka, b), resembling that 

 of Turritella. 



There are in the British Museum two specimens of 

 M. hrevia/is, from Goree, with opercula wliich agree closely 

 with that ot Epitoni'uvi (Scd/ariu) or Litlorina. The shcU- 

 characti-rs of the present spicies [snhdecussata) differ from 

 those of M. hievialis in some respects. The upper whorls 

 are longitudinally costate, the outer margin of tlie peristome 

 is not sinuated above, and the basal sinus is only faintly 

 develojied. It agrees with ..1/. inelanioides in being longi- 

 tudinally costate and the non-siimation of the labrum, but it 

 has not the maiked basal sinus as developed in that species. 

 Sinc<', however, so little is known at present with regard to 

 the animals, I think it preferable to leave this species in 

 Mesalia rather than Acirsa, or to create a new genua for its 

 reception. 



• Journ. I'roc. Roy. Soc. N..S.W. vol. xxiii. p. 202 (18S9). 



