1878.] ' LIGHTNING* AND ' PORCUPINE ' EXPEDITIONS. 4 1 5 



turbinata for the shell of the present species (Poli) ; Patella distorta 

 (Montagu) ; Orbicula norvegica (Lamarck) ; C. ringens and C. rostrata 

 (Hceninghaus) ; Discina ostreoides (Turton) ; Criopus orcadensis 

 (Leach), and Crania personata (Sowerby and others, not Lamarck) ; 

 var. alba=C. suessia (Reeve, in coll. M'Andrew) ! 



Mr. Dall was quite right in ascribing the original authorship of 

 the generic name crania to Retz, instead of to Philippson, as I had 

 erroneously stated. See Schrift. Berlin. Ges. naturf. Fr. Bd. ii. 

 p. 72, tab. i. f. 2-7, 1781. Philippson published the same name in 

 1788. 



Family II. Discinid^e, 

 Genus Discina. 

 Discina atlantica, King. (Plate XXIII. fig. 7.) 



D. atlantica, King in Proc. N. H. Soc. Dublin, 1868, vol. v. 

 p. 170 : Jeffr. in Ann. & Mag. N. H., Sept. 1876, p. 202. 



'Porcupine' Exp., 1869, St. 19 a, 1366 f. 



Off the west coast of Ireland, 1240 f. (Capt. Hoskyns). North 

 Atlantic, while fishing up the deep-sea telegraph cable in about 

 2400 f. (Sir James Anderson), « Valorous ' Exp., 1450 & 690 f. 

 (J. G. J.). « Challenger' Exp., near St. Paul, 1850 f. ; N. Pacific, 

 1875 f. & 2050 f. ; off Bermuda, 2180 f. (Davidson) ! 



I have also to thank Mr. Davidson for telling me of a mistake in 

 my short description of the animal in the 'Annals' above cited; 

 and I gladly take this opportunity of correcting it. The word mantle 

 ought to be substituted for " arms." 



D. atlantica is probably the same species as the Coralline-Crag fossil 

 which Mr. S. Wood at first doubtfully named D. norvegica and after- 

 wards D. fallens, and which Mr. Davidson at first doubtfully named 

 Orbicula lamellosa and afterwards D. fallens. But O. norvegica of 

 Sowerby ( = 0. lamellosa, Broderip) is a very different and tropical 

 species of Discina. 



The genus Discina appears to be the connecting link, at least analo- 

 gically, between the Brachiopoda and Conchifera through Anotnia, 

 both having a similar plug of attachment in the lower valve. 



EXPLANATION OF THE PLATES. 

 Plate XXII. 



Fig. 1. Terebratida caput-serpentis, young; to show the loop : p. 401. 



2. T. tuberata, p. 401. 



3. T. trigona, p. 402. 



4. T. subquadrata, p. 402. 



5. T. vitrea ; loop : p. 403. 



6. T. vitrea, var. sphenoidea ; loop : p. 404. 



7. T. tenera, p. 405. 



Plate XXIII. 



1. Terebratida septata, p. 407. 



2. Terebratella spitzbergensis ; loop : p. 409. 



3. Megerliajeffreysi; loop: p. 407. 



4. Atrefia gnomon, p. 412. 



