HALTOTIS. 19 



ornamented witli a, sort of dark-margined lamination, green 

 and purple predominating. H. ponderosa of C. B. Adams 

 is probably a more than ordinarily thick and convex variety 

 of this species. 



5. DISCUS, p. 32, Reeve. — Testa ovata, oblonga, tenuis 

 lasvis, obscure fusca, leviter spiraliter sulcata, oblique rugis 

 elongatis undata, angulo dorsali acuta, area marginali perpen- 

 diculariter profunda tuberculis foraminiferis prominentibus 

 subdistantibus, quaternis perviis ; spira prominenti sub- 

 terminali. — A larger range of specimens would probably 

 connect this with H. Kmnschatkana. 



6. Kamschatkana, f. 33, 34, Jonas. — Testa ovata, tumida, 

 fusca, versus spiram coloribus numerosis variegata, spiraliter 

 leviter sulcata, oblique rugis magnis tuberosis undulata 

 versus aream spiralem tumida, area marginali supra medium 

 concava, turn tumida, tuberculata ; tuberculis foraminiferis 

 prominentibus, subdistantibus, paucis.— It is chiefly in a 

 young state that the shell exhibits a mottling of various 

 colours, after which the colours tone down to brown or dull 

 red. There is a considerable swelling in the area from tho 

 suture and the middle, and the shells are less ovate-oblong 

 than those of discus, although intermediate specimens ma f 

 perhaps lead to the union of the apparent two species. 



7. CORRUGATA, f. 26, pi. iv. Gray. — Testa ovata, crassa, valde 

 convexa, spiraliter nodoso-lirata, nodulis irregularibus rug is 

 obliquas irregulares efformantibus ; spira decumbenti, fora- 

 minibus magnis, area marginali tuberculifera ; viridi fuscoque 

 fasciatim picta, intus vivide maculis purpureo-iridescentibus 

 ornata foraminibus magnis, paucis, tumidis. — A thick, convex 

 shell, with spiral knobbed ridges, crossed obliquely by 

 tubercular wrinkles. The interior pearl is brilliantly 

 iridescent with purple and green, and the muscular impres- 

 sion is curiously inlaid with dark semicircular lines ; tuber- 

 cular perforations few, large, tumid. 



8. MAEi^, f. 40, 41, Gray. — Testa setate juniori compla- 

 nata subrugata spiraliter latissime costata, deinde convexa, 

 tuberculata, ad marginem externum lobata, tuberculis forami- 

 niferis magnis. — The identity of H. marice of G-ray with 

 the dentata of Jonas must be taken partly on the authority 

 of Mr. Reeve, who compared his shell with drawings sent by 

 Mr. Jonas. In the specimen which I figure (41), the flatness 

 of the early growth is very remarkable, and so is the tran- 



