CEPHALOPODA OP THE HAWAIIAN ISLANDS. 
307 
to be slightly the superior in size. The widely separated habitat of the two leads one to believe that 
as both species become better known numerous other differences will undoubtedly be discovered to 
exist between them. 
Dr. Fisher informs me that when living the animal is an object of great beauty, the sheen of its 
delicate opalescence approaching that of mother-of-pearl. If it is so common a species in this region, 
it seems rather remarkable that no member of the genus has been brought to light from any other part 
of the Pacific. 
LARVAL OCTOPOD. 
There is a very ciuious but undetermined larval octopod in the Albatross collection from station 
3802, 150 fathoms, between the Erben Bank and Kaiwi Channel [S. S. B. 386]. 
Suborder DECAPOD A Leach 1817. 
Sephinia Rafinesque 1815, p. 139 {fide Binney and Tryon, p. ij). 
Decapoda Leach 1817 {fide Gray). 
Decacera de Blainville 1824 {fide Verrill) . 
Decacera de Blainville 1825, p. 366. 
Decapoda d'Orhigny 1845, p. 236. 
Decapoda Gray 1847, p. 205. 
Sepkinia Gray 1849, p. 2, 35. 
Decapoda H. and A. Adams 1853, vol. r, p. 25. 
Decapoda Keferstein 1866, p. 1438. 
Decacera Verrill 1881, p. 426. 
Arms normally lo in number; the fourth pair originating in special pouches into which they may be 
more or less completely retractile, and greatly modified to function as highly specialized prehensile 
organs. Suckers distinctly pedunculate ; their apertures equipped with homy or chitinous rings, which 
may be perfectly smooth, more or less dentate, or with the upper margin greatly enlarged and produced 
into a long incurved hook. Body short to elongate, rounded or pointed posteriorly, and always with 
well developed terminal or lateral fins. Head and mantle sometimes continuous in the nuchal region, 
but more often free and with a cartilaginous articulation. Gladius calcareous or homy; rarely absent; 
in one genus (Spirula) there is an internal coiled and chambered shell. Wherever hectocotylization 
occurs one or both of either the dorsal or ventral arms undergo the modification. 
Highly specialized photogenic organs of many types are of frequent occurrence. 
Division MYOPSIDA (d’Orbigny 1845). 
Decapoda Myopsidce d’Orbigny 1845, p. 237. 
Myopsidce Keferstein 1866, p. 1441. 
MyopsidcB Verrill 1881, p. 432. 
Myopsida Hoyle 1886, p. 16, no. 
Myopsida Pfeffer 1908, p. 15, 24. 
Eyes almost invariably covered by a continuous imperforate membrane or foldlike lid. Homy 
rings of suckers either smooth or dentate, but never falciform. 
There are also numerous important visceral characters such as the symmetrically bipartite liver, 
genital artery springing directly from the heart, etc. 
Family LOLIGINIDifi (d’Orbigny 1845 em.). 
holigtdae d’Orbigny 1845, p. 318. 
Loligidce Gray 1849, p. 36, 66. 
Loliginidce H. and A. Adams 1853, vol. i, p. 33. 
LoliginidcB Verrill 1S81, p. 433. 
LoliginidcB Pfeffer 1908, p. 24. 
LoliginidcB Naef 1912, p. 243; 1912a, p. 741. 
Body elongated and cylindric or cylindro-conical. Mantle free from head in the nuchal region but 
with a cartilaginous articulation. Eyes without lid-folds, the lens unintermptedly covered by the 
outer skin. Fins rhombic to sagittate and terminal, or nearly as long as the mantle and marginal; more 
