64 THE NAUTILUS. 



CONTRIBUTIONS TOWARDS THE KNOWLEDGE OF THE MOLLUSCA OF 



MADAGASCAR. 



BY C. F. ANCEY. 



Helicarion (?) Dautzenbergianum Anc. 



Testa imperforata, convexo-depressa, angulata, tenuis, pellucida, 

 nitens, corneo-virens, supra angulum medianum fascia rubrofusca sat 

 angusta circumdata, indistincte et obsolete lineis radiantibus sub- 

 plicosa. Spira depresso-conoidea, subobtusa, convexa. Anfractus 

 4-5 celeriter crescentes, subconvexi, sutura distincta sed baud pro- 

 fun da ; ultimus magnus, dilatatus, utrinque convexus, medio angu- 

 latus, basi subtumidus. Apertura ampla, distincte obliqua, extus 

 angulata, lunato-oblonga, leviter supra convexo-producta, basi regu- 

 lariter usque ad columellam arcuata, marginibus remotis. 



Diam. maj. 18, min. 15^, alt. 9^, alt. apert. (oblique) 9 mill. 



Hab.: " Montagne d' Ambre," N. Madagascar. 



A very remarkable species on account of the keel and its very 

 peculiar shape and coloration. It may, perhaps, be referable to 

 Euplecta or Hemiplecta. 



Enphcta oxyacme Anc. 



Testa fragillima, subimperforata, conico-trochiformis, parum 

 nitens, opacula, corneo-lutescens, concolor, sub valida lente lineis 

 confertissimis incrementi notata et striis argutis permultis spiralibus 

 decussata, subtus paulo nitidior. Spira elevata, perfecte conica, 

 rectilinearis, acuta. Anfractus C regulariter crescentes, priores con- 

 vexiusculi, infer! applanati, sutura lineari, appressa ; ultimus acute 

 et compresse in medio carinatus, infra convexus, supra carinam 

 planodeclivis, antice haud deflexus. Apertura lunata, extus angu- 

 lata, subobliqua, marginibus distantibus, supero recto-declivi, basali 

 regulariter arcuato, columellari leviter supra perforationem parvulam 

 expansiusculo, earn fere prorsus occultante. 



Diam. maj. 13^, min. llf, alt. apert. oblique of, alt. 9^ mill. 



Hab.: Antankaratra Country (Humblot). 



Of the same shape and size as Rotula argentea, Reeve, but of 

 thinner texture and different color. It may belong to the same 

 genus, but is perhaps related to Euplecta (T) fenerrff'ensis, Angas. 

 The generic reference, therefore, is doubtful. 



