41 137 
phagus” from St. Maurice and Bourbon agrees exactly with L. gracilis, Phil., but yet 
Puitrppr and Dunker refer it to L. teres, Phil.) Dunker! thinks that L. teres is 
closely analogous to L. niger, @Orb. (= L. Antillarum, Phil.), and is perhaps only a 
variety of the same. The reason for this must be sought in the opinion expressed 
in his diagnosis of L. teres, Phil.: “epidermis nigro-castanea, in dorso et subter 
umbonibus laevis, in latere ventris simili modo striata ac in Lithophaga nigra.” 
The most important mark of distinction between the West Indian L. niger, d’Orb., 
and the East Indian L. gracilis, Phil., is, as far as I can see from the material at 
my disposal, precisely this epidermal striation. In L. gracilis, Phil., these trans- 
verse lines extend almost to the anterior end (diminishing gradually in size) and 
only a small portion of the outermost part of that end is quite smooth; in 
the posterior part, the striation is usually continued somewhat farther than in 
L. niger. On comparing two specimens — one of each of these species — of equal 
size (e.g. 49 mm.), the result will be as follows: in L. niger (from St. Thomas) the 
striation is continued beyond 32 mm., as measured along the lower margin of the 
shell, while in L. gracilis (from the Gulf of Siam) it covers 40 mm. 
Lithodomus straminea, Dunker. 
Lithodomus stramineus, DUNKER, REEVE, Conchol. icon, X, Lithodomus, Sp. 11. 
Lithophaga straminea, — Dunker in Martini u. Caemnirz, Conchyl. Cabin., VII, 3 Abth. A, p. 6, 
pl. 2, figs. 1—2. 
Koh Chang, very low tide (1). 
Long. 22 mm. 
Distribution: — Madras (MELVILL & STANDEN), the Gulf of Manaar (THuRSTON). 
— Mast Head Reef, Queensland (HEDLEY). 
The habitat “West Indies“ given in Cumine’s collection, is undoubtedly due 
to an error. 
J. MasitLe and G. te Mesie record? Lithodomus lithophagus L. from Poulo 
Condor; CrossE* is right in doubting the correctness of this determination. Is it 
not more probably L. straminea, Dkr., that has been found? 
Lithodomus Malaccana, Reeve. 
Lithodomus Malaccana, RrEve, Conchol. icon., 1858, X, Lithodomus, Sp. 20. 
Lithophaga Malaccana, — Martini u. CHEMNITZ, Conchyl. Cabin., VIII, 3 Abth. A, p. 20, pl. V, fig. 1. 
Lithodomus subula, — Conchol. icon., X, Lithodomus, Sp. 26. 
Lithophaga = — -— Martini u. CHEMNITz, Conchyl. Cabin., VIII, 3 Abth. A, p. 21, pl. V, fig. 13 
(figs. 11—122). 
_ cavernosa, DuNKER, MARTINI u. CHEMNITZ, loc. cit., p. 7, pl. II, figs. 5—6; pl. V, figs. 15 —16 
= reliculata, = — = loc. cit., p.19, pl. V, figs. 9— 10. 
1 MarTini u. CHEMNITZ, Conchyl. Cabin., VII] Bd., 3. Abth., p. 13. 
2 Journal de Conchyl., XIV, 1866, p. 118. 
5 loc. cit. p. 119. 
D. K. D. Vidensk. Selsk. Skr., 7. Reekke, naturvidensk. og mathem. Afd. V. 3 
