98 PROCEEDINGS OF THE ACADEMY OF [18T9. 



6. Tr. tethydea, Delle Chiaje, Mem. iv. 1829, t. 2, fig. 20, Ed. 2, v. p. 74. 



.Marc Mediterran. 



7. Tr. Costa, Verany, Catal. p. 23, t, ii. fig. 7, 8, 184G. Mare Mediterran. 



8. Tr. Meyeri, Verany, Zool. des Alpes Marit. p. 871, 1862. Mare Medi- 



terran. 



9. Tr. acuminata, 0. G. Costa, Statistica fis. ed econ. dell'isola di Capri, 



ii. 1, 1840, p. 1840, p. GO, Tav. V. fig. 1 a. b. 1 Mare Mediterran. 



10. Tr. tetraquetra (Pallas). Mare Pacificum. 



11. Tr. Palmeri, Cooper, Proc. Cal. Acad. Sci., ii. 18G3, p. 207. Mare 



Pacificum (Cal.). 



12. Tr. Hawaiensis, Pease, Proc. Zool. Soc, xviii. 18G0, p. 33. Mare 



Pacificum. 



13. Tr. pallida, Stimpson, Proc. Phil. Acad. Nat. Sci., vii. p. 388, 1856. 



Mare Capense. 



14. Tr. cucculata, Gould, Expl. Exp. Shells, 1852, p. 308. Mare Atlant. 



occid. (Brasilia). 



15. Tr. plebeia, Johnst. Mare Atlant. 



16. Tr. lineata, Alder and Hancock. Mare Atlant. 



17. Tr. (Duvancelia) gracilis, Risso, 1. c. p. 38. Mare Mediterran. 



18. Tr. manicata, Desk., Tr. de Conchyl. 1839-1853, expl. des pi. p. 59, 



pi. 93, fig. 2. 

 ? NemocepTiala marmorata, A. Costa, Illustr. di due generi di Moll. 

 Nudibr., Atti. della R. Ac. Sci. di Napoli, iii. No. 19, 18G9, Tav. 

 . fig. 6-8. Mare Mediterran. 



I. Tritonia tetraquetra (Pallas), PI. III. f. 13-16 ; PI. IV. fig. 5-12 ; PI. V. fig. 1-2. 

 Li max tetraquetra, Pallas, Nova Acta Petrop. ii. p. 237, 239, Tab. V. f. 22, 



1788. 

 Doris tetraquetra, Gmelin; S. N. ed. xiii. t. G, p. 3106, 1789. 



Color animalis cinerascens. 



Hab. M. Pacific, septentr. (Insulae Kurilse, Aleutian^). 



This species was detected by Pallas, and described (1. c.) among 

 his "marina varia nova et rariora;" and immediately afterwards 

 was inserted bj r Gmelin in his undigested genus Doris; it seems 

 not to have been mentioned since that time, nor recognized by 

 any of the different explorers of the Pacific. 2 



Pallas got the animal from the Kuril Islands, "where the inha- 

 bitants eat it, raw or cooked, and where it is known b3^ the name 

 of Tochni." He says nothing about the colors of the animal, only 



1 On account of the rarity of the work cited (kindly given to me by Prof. 

 A. Costa, of Naples, the son of the author) this species has only been men- 

 tioned by Gray, Guide, i. p. 218. 



2 Cuvier (1. c. p. 4) mentions the possibility of this species of Pallas 

 being a Tritonia. 



