PIREN A. 



Plate I. 



Genus PIRENA, Lamarck. 



Testa subulata vel turrita, anfractibus nunc lavibus nunc 

 costatis vel striatis. Aperlura profundi bisinuata. 

 Columella ad basin Iruucata, margine calloso-incurvo 

 ant refexo. 



Shell subulate or turreted, whorls sometimes smooth, some- 

 times ribbed or striated. Aperture deeply bisinuated. 

 Columella truncated at the base, with the margin cal- 

 lously incurved or laminated. 



The genus Pirena, taken, agreeably with the plan of our 

 work, in its Lamarckian sense, comprehends two very dis- 

 tinct groups ; one represented by the old Linnsean type, 

 Strombus ater (Pirena terebralis, Lamarck), the other re- 

 presented by Lamarck's Pirena spinosa, and constituting 

 Bowditch's genus Melanatria. 



The Pirena proper are solid, elongately tapering shells, 

 with only a single moderately sized lip-sinus, the second 

 sinus being at the base, inhabiting rivers in India, Ceylon, 

 the Molucca and Philippine Islands, and extending south- 

 ward into New Caledonia. 



The Pirena' of the Melanatria type are inflated, tubercled 

 species, having the outer lip broadly double-sinuated, with 

 the columellar margin not callously incurved, but reflected 

 in the form of a continuous flat lamina ; and they are na- 

 tives of Madagascar and Western Africa. An intermediate 

 link between the groups is presented in P. lingulata. 



The species of Pirena, it will be seen, are few, and 

 the geographical distribution of the two groups is confined 

 respectively to the localities above mentioned. 



Species 1. (Mus. Cuming.) 



Pirena nana. Pir. testa subci/lindraceo-subulatd, in- 

 tense atrd, anfractibus decern ad undecim, concavo-pla- 

 natis, obscure minute crispato-striatis ; aperturd par- 

 vd, margine columellari. profundi; calloso-incurvo, la- 

 bro externo pereffuso. 



The dwarf Pirena. Shell somewhat cylindrically su- 

 bulate, shining-black, whorls ten to eleven, concavely 

 flattened, obscurely minutely crisply striated ; aper- 

 ture small, columellar margin deeply callously in- 

 curved, outer lip much effused. 



Hah. New Caledonia. 



Of an uniform small size and subcylindrical outline, 



with a black, shining, horny exterior exhibiting here and 

 there assemblages of minute, crisped striae. 



Species 2. (Fig. a, 6, Mus. Cuming.) 



Pirena Cantori. Pir. testa recto-elongntd, olivaceo-ni- 

 grd, anfractibus angustis, plano-convexis, oblique con- 

 torto-siriatis ; aperturd parvd, brevi, margine columel- 

 lari profundi calloso-incurvo, labro externo pereffuso. 



Cantor's Pirena. Shell straightly elongated, olive-black, 

 whorls narrow, flatly convex, obliquely tortuously 

 striated ; aperture small, short, columellar margin 

 deeply callously incurved, outer lip much effused. 



Hab. Penang. 



Distinguished by a less subulate form than the allied 

 species of this genus, the whorls being narrower and the 

 aperture proportionally shorter. It is named in manu- 

 script in Mr. Cuming's collection after Dr. Cantor. 



Species 3. (Pig. a, b, Mus. Cuming.) 



Pirena picta. Pir. testa acute cylindraceo-snbulatd, 

 tumiduld, nilente-atrd, sordide luteo profuse undulatd 

 et vittatd, anfractibus septemdecim ad octodecim, con- 

 vexo-planatis, oblique contorto-striatis ; aperturd me- 

 diocri, margine columellari calloso-incurvo. 



The painted Pirena. Shell sharply cylindrically su- 

 bulate, somewhat swollen, shining-black, profusely 

 waved and filleted with dingy yellow, whorls seven- 

 teen to eighteen, convexly flattened, obliquely tortu- 

 ously striated ; aperture moderate, columellar mar- 

 gin callously incurved. 



Hab. Ceylon. 



This species, hitherto confounded with P. atra, should, 

 I think, be distinguished. It is of more swollen propor- 

 tions, fewer-whorled, void of ridged strise at the base, and 

 exhibits a more decided variegation of yellow painting. 



Species 4. (Mus. Cuming.) 



Pirena pagodus. Pir. testa subutato-turriid, nitente- 

 atrd, obscure oblique luteo-strigatd, anfractibus qua- 

 tuordecim ad quindecim, declivi-convexis, inferne ab- 

 rupti angulatis, oblique substriatis ; aperturd mediocri, 

 margine columellari calloso-incurvo. 



November, 1859. 



