THE CONCHOLOGIST. 



On a Specimen of Pleurotomaria Adansoniana, Crosse & Fischer, 



FROM TOBAGO, WEST INDIES. 



By R. J. LECHMERE GUPPY, C.M.Z.S. 



[At a meeting of the Zoological Society, 31-d November, 1891, Mr. R. J. Lechmere Guppy, C.M.Z.S., 



exhibited and read some remarks on a fine specimen of t^kurotomaria from the island of Tobago. 



A fuller account of this specimen was published in the Transactions of the Natural History and 



Scientific Society of Trinidad in 1890. From this latter account we reprint the following notice]: — 



Amonc some shells placed in the Tobago Court at the Trinidad and Tobago Exhibition of 1890 my 



attention was drawn to a fine specimen of Pleurotomaria. On inquiry, I found that the shell was 



the property of a gentleman of Tobago, ofif which island it had been taken. The original owner having 



died, I was unable to obtain complete particulars respecting the capture of the shell, which, after some 



negotiation, became my property. 



In an interesting paper by Dr. Henry Woodward, F.R.S., published in the "Geological Magazine"* 

 for 1885, some particulars are given respecting the fossil and recent species of the genus, which I avail 

 myself of. According to this author the number of fossil (extinct) species of Pleurotomaria is 1,156, of 

 which 226 are British. The genus was supposed to be entirely extinct until 1855, when the first living 

 example was found by M. Beau oft" Mariegalante. This was described by Fischer and Bernardi in the 

 "Journal de Conchyliologie" for 1856 (p. 160, pi. v.) as PI. Ouoycma. This specimen, 45 millimetres in 

 height, was in 1873 purchased by Miss de Burgh, of London, for ^25, a sum, as stated by the editors of 

 the "Journal de Conchyliologie," rather below than above the real value of so rare a shell, of which, as 

 stated by Woodward, only three examples are known up to the present time. 



The next discovery of Pleiirotomaiia was in 1861, when a single imperfect specimen of another 

 species came to light. This was described as Pi. Adansoniana in the "Journal de Conchyliologie" for 

 that year (p. 163, pi. v.). This example was 80 millimetres in width and 74 in height. Another more 

 perfect specimen of this species was taken near Guadeloupe, and described in "Journ. Conch." 1882 (p. 12, 

 pi. i.). This one was 85 millimetres in height and 91 in diameter. 



It is to this species that the Tobago shell is to be referred. Besides the two examples named 

 above, three others are known. 



Two other living species of Pleurotomaria have been described, namely, PL Beyrichi in 1877, and 

 PL Rumphii in 1879. The former was found in Japanese waters, and of it four examples are known. 

 The latter is stated to be from the Moluccas, and only a single specimen is known. Consequently, 

 according to the enumeration given in Woodward's paper,* there were up to the present time thirteen 

 specimens of recent I''lei/rotomaria in existence, belonging to four species. The Tobago specimen is 

 therefore the sixth of the species and the fourteenth of the genus known as recent. 



The dimensions of PL Quoyana and PL Adansoniana have already been given ; those of the other 

 two species are indicated below : — 



Height. Diameter. 



PL Rtcmphii ... ... 170 mm. ... 1 90 mm. 



PL Beyrichi ... ... 82 „ ... 83 „ 



The dimensions of our specimen of PL Adansoniana are as follows : — Total height, 150 mm.; greatest 

 diameter, 160 mm.; height of aperture, 50 mm.; width of umbilicus, 30 mm.; length of fissure, 220 mm.; 

 width of fissure, 5 mm. This, therefore, is the second in size of the specimens of recent Pleurotomaria 

 in existence. The coloration consists of a number of flames or irregular, more or less zig-zag, spots of 

 flesh red, passing into orange, arranged on a ground of very pale flesh tint. The apex is finely pointed, 

 yellow, and almost smooth. When viewed through the funnel-shaped umbilicus and held to the light it 

 appears almost transparent. The supramedian fissure occupies the larger half of the contour of the 

 shell. The characters generally correspond very closely with those given in the "Journal de Conchyliologie," 

 1882, p. 12. The colour of our specimen would appear, if we may judge by the figures, to be paler than 

 the previous examples. It is in almost perfect condition, and looks as if when found it had had the 

 living animal still in the shell. 



[The specimen was purchased from Mr. Guppy, and is now the property of Mr. Robert F, Damon, 

 of Weymouth.] 



* Decade III., Vol. 2, pp. 433-439. PI. XI., Fig. i. 18S5. 



