ZOOLOGY. 363 



cuttle-tish, but iu the old it is a single tube; (2) in nautilus the eye is a 

 simple cavity opeuiug externally by a minute aperture, as is the case iu 

 the embryo cuttle ; (3) iu nautilus the auditory orgaus are close beneath 

 the eyes, and so they are iu the embryonic cuttle, but in the mature 

 dibranchiates they have approximated on the ventral side ; (4) in nau- 

 tilus the tentacular and labial processes are more or less flattened and 

 lie one within the other, and in analogous manner in the dibranchiates 

 the arms rise as broad Hat processes, one pair within the others. Mr. 

 Blake contends (with Valencdennes) that the processes (six or eight) 

 from which the tentacles originate in nautilus are homologous with the 

 arms of the cuttle- tishes, and that the tentacles are homologous with the 

 suckers. The aptychus-bearing "hood'- of the nautilus may be homolo- 

 gous either with the anterior i)ort of arms of the dibranchiates (the ar- 

 gonaut thereby secretes its shell) or with the "neck-plates" just behind 

 the eyes and in front of the "bone" of Scjnd, or the generalized basis 

 of both; but this the embryology of nautilus must determine. The shell 

 of nautilus it is thought may be represented in the dibranchiates by 

 the shell of Sjyindd, the phragmacone of a Belemnite, and the nuicro of 

 a Sepia-bone. The ink-bag which is developed late in the embryological 

 history of the cuttle-fishes does not exist at all iu nautilus. 



THE CEPnALOPODS OF EASTERN NORTH AMERICA.* 



In the earlier works upon the moUusks of the eastern (;oast of Xorth 

 America only three or four species w^ere recorded, aud until within the 

 last few years that coast was supposed to have few inhabitants repre- 

 senting that class. Since the institution of the labors of the Fish Com- 

 mission, however, a number of new forms have been made known, and 

 some of' them represent new genera. Among the most noteworthy are 

 species of gigantic cuttle-fish, of which quite a large nundjer of speci- 

 mens have now been discovered iu various places on the Great Banks, 

 and around or near the island of Kewfoundland. The following are 

 all the species that have been made known as inhabitants of the north- 

 eastern coast of the United States to the end of 1880. 



Decapods. 

 Arch iteuthis princeps Y. Eossia Hyatti Y. 



Uarveyi Y. sublccvis Y. 



Stlienoteutliis mcgaptera Y. Sepiola leucoptera Y. 



Ommastrcphis illieehrosa (Les.) V. Logilo Pealei (Les.) V. 

 Tuonius pavo (Les.) Steenstrup. pallida Y. 



hyperhorcus Steenstrup. Parnsira catennlata (Fer.) Steen- 



Hlstioteuthis ColUnsii Y. strnx). 



CalUteuthis reversa Y. Hcteroteuthis tenera Y. 



* Verrill (A. E. ). Syuopsis of tlio Cephalopotlii of the iiortliea stern coast of America ; 

 brief Contributious to Zoology from the Museum of Yale College. No. XLVi. With 

 Y)lates XII to xvi. Am. Journ. Science, (3), vol. xix, pj). 284-JU5. Also, notice of the 

 remarkable Marine Fauna occupying the outer banks of the southern coast of New 

 England. Am Journ. Science, (3,) vol. xx, iij). 390-41)3. 



