cclxvi 
Decapoda. — — MOLLUSCA. Pteropoda. 
of the genus. Most of the specimens were kept 
alive a few days in order to observe tlieir habits.” 
Like other species noticed, it is nocturnal in its 
habits. “'I'he length of the largest specimen, in al- 
cohol, exclusive of its arms, is oise and three quarters 
inches ; breadth of body one and one q\uirter. When 
living, the color was usually j)ale, translucent, bluish- 
white, thickly speckled with light orange-brown and 
dark brown.” Specimens were taken off Head Har- 
bor, Oampo Bello, in seventy-five and eighty fathoms, 
and off Grand Menan. Prof. Verrill concludes ; “ I 
first dredged this interesting species while on the 
‘ Mosswood,’ in company with Prof. Baird, in honor 
of whom I have named it. * * * There is no 
other species known on the American coast north of 
(Jape Hatteras. 'I’he sonthern species is very much 
larger, and very different in many respects.” 
Octopus granulaius, LamarcTc . — During the dredg- 
ing carried on by the U. S. Fishery Commission in 
Vineyard Sound, in the summer of 1877, a specimen 
of Octopus was taken, which is supposed to be iden- 
tical with this species. 
DECAPODA. 
'I’he name of this group, which means ten-footed, 
is derived from its having eight real arms and two 
tentacular ones, called tentacles ; the latter being 
elongated and usually smooth and round, excepting 
near the ends, where they are expanded and armed 
with pedunculated suckers, or discs, each with a 
horny ring, the exterior surfaces of which are minute- 
ly serrated. The body is oblong, and provided with 
a pair of fins. In Sepia, and several other genera, the 
tentacles are completely retractile into pouches situ- 
ated beneath the eyes ; in the familiar genus Loligo 
they are partially retractile in the same manner. 
'J'hese long arms serve to seize their prey, and con- 
vey it to the mouth, and, in the genus Chiroteuthis, 
measure six times the length of the short ones. A 
portion of the sucker-armed extremity of the tenta- 
cles is adapted for the close contact and adhesion of 
the two for a short distance, thus forming an exact 
counterpart of a forceps, and serving precisely the 
purposes of that implement. A Fish seized with such 
a power is surely conveyed through the flexibility 
and contractile power of the tentacles to the vora- 
cious jaws of the animal. 'I’hese jaws are almost an 
exact copy of the beaks of a Parrot. 'I'he shell of 
the living Decapods is either a horny pen (gladius) 
or calcareous bone. The former is a colorless, trans- 
parent, mica-like object, in some species curiously 
like a quill pen ; even the point and truncated nib of 
the form is simulated. 
Family LOLIGO PSIDJE. — ^Loligopsis pavo com- 
prises the whole of this family in our North Atlantic 
waters. 'I'his creature inhabits the high seas, and is 
a powerful swimmer. Stimpson found it along the 
New England coast. 
Family ONTCHO'rEU'I’HIDAE. — The animals 
comprising this family are called Squids or Calani- 
aries, and frequent the open seas of all climates. 
'I'he genus Omniastrephes and two species, sagittatus 
and bartrami, are all tliat belong to the family on 
the North Atlantic shores. 'I'he former species is 
especially abundant on the shores of Cape God. 
Prof. Verrill informed us that he has seen the Squid 
dart upon Fishes, and nip out a piece of the neck or 
back of the head, and this he regarded as their usual 
method of capturing prey. 
Family LOLIGINIDAE consists of the genus 
Loligo, with the two species, punctata and peali. 
'I’liB former,” says Dr. DeKay, “ is the only one I 
have noticed on the coast of New York ; the latter 
is found on the coast of South Carolina.” 
Family SPIRULIDH5 is especially circumscribed, 
but one living genus being found. Spirula fragilis is 
the only example known. The shell is found occa- 
sionally thrown ashore on our beaches; and is very 
abundant on tlie Gulf coast, associated with Jan- 
thina. We have seen the beaches lined with them 
at high-water mark. 'I’he living animal has very sel- 
dom been seen. 'I’his little shell approaches near in 
structure to the beautiful Nautilus, and the ancient 
and extinct Orthoceras and Ammonite. 
Class— PTEROPODA. 
In this class the head is more or less distinct ; there 
are no eyes; the mouth is often furnished with cup- 
shaped ap[)endages. On the sides of the mouth there 
are two appendages or fins, and two or four in 
others, on tlie sides of the body, between the head 
and abdomen, often furnished with a small inter- 
mediate lobe between them, apparently the rudiment 
of a foot of Gasteropods. 'The body is ovate or 
roundish, often enclosed in a thin, conical, cylindri- 
cal, or sub-globular shell, with a transverse, con- 
tracted mouth. 'The individual is of one sex, prob- 
ably. 'I’lie animal is free, floating on the surface of 
the ocean, aided by the use of its fins. Most are 
nocturnal or crepuscular in habit. Four families 
are enumerated as belonging to this class, embraced 
in two orders. Little is known of these forms, as 
they are mostly found on the broad ocean. Some 
species are the principal food of the Right Whales. 
Order— 'I’HECOSOMATA. 
In this order the gills are internal, and the body 
of the animal enclosed in a shell. 
Family CAVOLINIDaE. — 'I’ he shells are symme- 
trical, elongate, or globular, and calcareous in struc- 
ture. 'I’lie gills are in pairs. The animal has two 
united tins, without any posterior foot-like appendage 
between them. One genus, Diacria, and one species 
comprise tliem. 
Famii.y CYM BULHDJE.^ — 'I’his family embraces 
but one genus. Psyche, and one species, P. globosa. 
'I’he body is round and diaphanous, with a beautiful 
purple visceral sac. 
