460 ZOOLOGY. 



before (U. S. Geol. Surv. 40tli Par., v. 4, p. 176, pi. 17, f. 19, 19 a) from 

 specimens obtained in the Laramie group, "which holds a transitional 

 position between the Mesozoic and Cenozoic series" (Nature, v. 25, pp. 

 101-102). Dr. White also was of the belief that the ^'■Melania (Sermyla) 

 admiraUlis^^ of Tanganyika Lake is "evidently congeneric with" the 

 ^^Goniohasis Cleburni," described by him from the same formation. Mr. 

 Smith, however, thought that it was "decidedly unadvisable at present 

 to locate the two forms in question in the same genus" (Nature, v. 25, 

 p. 218). In view of the known facts of distribution coincident with 

 structural characteristics of the Melaniids and related forms, it seems to 

 be premature, without direct comparison, to identify the extinct Ameri- 

 can and living African shells as congeners. 



The quasi-representative forms are probably not only not isotypes, 

 but simply mimotypes, and it is quite improbable that any of the Ameri- 

 can Melaniiform mollusks are necrotypes* of Africa. 



CEFHALOPODS. 



Dihranchiata. 



Girod (P.)- Structure et texture de la poche du noir chez lea C^phalopodes dea c6tes 



de France. Compt. rend. Acad. Sc, Paris, t. 92, pp. 966-968. 

 . Les vaisseaux de la poche du noir des C6plialopodes. Compt. rend. Acad. So., 



Paris, t. 92, pp. 1241-1243. 

 Ihering (H. von). t!ber Aptychen und Anaptychen. Kosmos, v. 9, pp. 142-144. 

 . Das Verhalten der Siphonalducte und die Descendenz der Cephalopoden. 



Kosmos, V. 9, pp. 145-149. 

 Owen (Rich.). Descriptions of some new and rare Cephalopoda. Trans. Zool. Soc. 



London, v. xi, pp. 131-170. 

 Yung (E.). Recherches exp6rimentale8 sur Taction des jioisons chez les C6phalo- 



podes. Mittheil. Zool. Station Neapel, v. 3, pp. 97-120. 

 Verrill (A. E.). Giant Squid (Architeuthis) abundant in 1875 at the Grand Banks. 



Am. Journ. Sc. (3), v. 21, pp. 251-252 ; Ann. ^ Mag. Nat. Hist. (5), v, 7, pp. 351-352, 



Gigantic Cuttle-Fishes. 



The gigantic cuttle-fishes have been specially studied by Professor 

 Verrill, and much light has been thrown on the subject by his researches. 

 The largest of the class appear to belong to the family of Ommastre- 



*The geography of animals and plants may he discussed with increased precision 

 and terseness by the use of several terms, e. g. : 



Mimotypes (fu/uo^, mimic; tvttoc, form): Forms distantly resembling each other, 

 but fulfilling similar functions, and thus representing each other in dift'ercnt faunas; 

 e. g., (1) the Shrews of Europe are mimotypes of the An techinus of Australia; (2) the 

 Sloths of South America, of the Phascolarctida3 of Australia, etc. By the use of this 

 term, the word " analogue" may be relieved of a part of the burden borne by it. 



ISOTYPES (Iffof, equal or like; rvnog, form): Forms common to different countries: 

 e. g., the Shrews are isotypes in Europe and North America, etc. 



Necrotypes (veKpoc, dead, and Tvnog, form) : Forms formerly existent in a country, 

 but now extinct; e. g., the horses and rhinoceroses are necrotypes of North America, 

 indigenous species having once flourished on that continent, but become exterminated 

 in prehlBtoric times. 



