MARINE MOLLTJSCA OF MADEIRA. 245 



animal's head, when retracted it points towards the canal. — 

 L. 0-8. B. 0-34 



Not common. Madeira, 50 fms. ; Labra ; Punta de Sao Lou- 

 renco (Lowe, Johnson, Watson). 



This is the species which McAndrew gives at p. 40 of his 

 Eeport as living on the " rocks " of the " shore ; " " rare, species 

 obtained in Canaries ; " see also I. c. p. 82, where he says of it 

 " rare — white." There are unnamed specimens of the species in 

 his collection both at Cambridge and in the British Museum. 

 On the shore-rocks I certainly never found it. Mr. Johnson's 

 one young specimen came from a deepish-water coral, and 

 Mr. Lowe's were dredged in Labra from a depth of some 

 fathoms : but one or two of them are occupied by hermit-crabs, 

 whose presence seems to indicate shallow water. 



This species most nearly resembles T. fusidus, Broc., but it is 

 narrower, flatter, with a narrower mouth ; the sculpture is very 

 markedly different. It has some likeness to Murex cristatus, 

 Broc , and very worn specimens may be easily confounded, but 

 the two species are unmistakably different. I feel by no means 

 sure that this is not 31. productus, Bellardi, Moll. Terr. terz. 

 Piemonte, pt. i. p. 99, vii. 6 ; but his description is very vague, 

 his measurements suggest a larger and narrower shell, and no 

 specimen is available. 



Fam. Cerithiida 

 Gen. Bittium, Leach. 



13. Bittitjm depauperatum, n. sp. 



Shell : a tall narrow cone with a contracted and produced base, 

 barely translucent, slightly glossy, of a uniform pale yellow 

 colour, occasionally palely brown banded. Sculpture: there are 

 weak spiral threads, of which, on the body-whorl, five lie above 

 the periphery and four on the base ; these last are not cross- 

 hatched but simple ; the furrows which part these ridges are 

 shallow and narrow ; the number of the ridges and furrows is 

 fewer on the earlier whorls, on the 2nd whorl tbey are only two; 

 the threads are studded with rather blunt round tubercles which 

 run in continuous and somewhat diagonal lines across the whorls 

 — about 20 of these lines are on the last whorl ; parallel to these 

 cross-lines the whole shell-surface is feebly and microscopically 

 undulated. Colour yellowish white, with occasionally a palish 



