1885.] ' lightning' AND 'porcupine ' EXPEDITIONS. 59 



uppermost spiral row : mouth rhomboidal ; and all other characters 

 similar tn those of T. perversa. L. 0"6, B. 0'15. 



'Porcupine' Exp. 1870: Atl. St. 16, 24, 27-30; Med. Adventure 

 Bank. 



Distribution. Bay of Biscay (« Travailleur' Exp. 1882), Sciacca, 

 Sicily (Monterosato), G. Mexico (Pourtalis); 125-731 fms. 



Distinguishable from T. j)erversa by being more slender, and 

 having more prominent tubercles so as to give the shell a rougher 

 aspect. The base is also more square aud as if truncated. 



A. Typical ; apex acuminated. 



1. Cerithiopsis tubercularis, Montagu. 



Murex tubercularis, Mont. Test. Brit. p. 270. 



C. tubercularis, B. C. iv. p. 266, pi. iv, f . 5 ; v. p. 21 7, pi. Ixxxi. 

 f. 1. 



'Lightning' Exp. St. 5. 



'Porcupine' Exp. 1870: Atl. 3a, 13, Vigo B. ; Med. Adventure 

 Bank (var. nana). 



Distribution. Christiansund (Lilljeborg)\ to Alexandria(PoK50«6?/)!, 

 W. Africa ('Talisman' Exp.) !, Madeira {Watson) !, Canaries (Me 

 Andrew) !, Boston Harbour southwards {C. B. Adams and others)!, 

 G. Florida {Ball), Queen Charlotte's I. {Whiteaves) ; 0-1039 fms. 



Hab. Littoral and laminarian zones. 



Fossil. Miocene : Vienna Basin, Calabria, and ?Rhodes. Pliocene : 

 Red aud Coralline Crags, Belgium, Biot, Italy, and Rhodes. Post- 

 tertiary : Norway, Scotland, Ireland, and ? Rhodes. 



Cerithium pygni(eum, Phihppi, Oerithium henkelivsii (posthac 

 henkelii), Nyst, Cerithiopsis acicula and C. miriima, Brusina. Not 

 Cerithiopsis tuberculata, P. Carpenter. 



I must still retain my opinion that C. clarJcii, alias bilineata, or 

 coppolce, is merely a monstrous or irregular form of the present 

 species. One of my specimens, which has only two rows of 

 tubercles on the lower whorls, has three rows on two of the upper 

 whorls. The lower rows seem to have become squeezed together 

 and elongated. A small and slender variety is C. acicula of Brusina, 

 = Cerithiolum dextrum, ^Yatson, ex typis. I regard Cerithiopsis 

 atalaya of Watson as another variety. 



Dr. Tiberi found large and small varieties of C. tubercularis 

 living with Modiolaria marmorata in the tunic or outer coat of 

 Ascidia mentula at Naples. Were the two moUusks commensal or 

 quasi-parasitic, like species of Eulima and Stili/er 1 



De Blainville in his ' Faune Frangaise ' included not only this 

 species but also Cerithium reticulatum and Triforis perversa in his 

 Cerithium tuber culare. 



The apical or top whorls in fresh and perfect specimens, when 

 examined under a microscope, are seen to be very finely and closely 

 ribbed lengthwise. Occasionally specimens have four rows of 

 tubercles on the lower whorls. 



